Joint Transmit Signal and Beamforming Design for Integrated Sensing and Power Transfer Systems - Mayer, Kenneth; Shanin, Nikita; You, Zhenlong; Lotter, Sebastian; Brückner, Stefan; Vossiek, Martin; Cottatellucci, Laura; Schober, Robert (IEEE International Conference on Communications, ICC 2024, 2024)
Integrating different functionalities, conventionally implemented as dedicated systems, into a single platform allows utilising the available resources more efficiently. We consider an integrated sensing and power transfer (ISAPT) system and propose the joint optimisation of the rectangular pulse-shaped transmit signal and the beamforming vector to combine sensing and wireless power transfer (WPT) functionalities efficiently. In contrast to prior works, we adopt an accurate non-linear circuit-based energy harvesting (EH) model. We formulate and solve a non-convex optimisation problem for a general number of EH receivers to maximise a weighted sum of the average harvested powers at the EH receivers while ensuring the received echo signal reflected by a sensing target (ST) has sufficient power for estimating the range to the ST with a prescribed accuracy within the considered coverage region. The average harvested power is shown to monotonically increase with the pulse duration when the average transmit power budget is sufficiently large. We discuss the trade-off between sensing performance and power transfer for the considered ISAPT system. The proposed approach significantly outperforms a heuristic baseline scheme based on a linear EH model, which linearly combines energy beamforming with the beamsteering vector in the direction to the ST as its transmit strategy.<br

Kalman Filter assisted Tracking of Microparticles in Hollow-Core Photonic Crystal Fibers for Sensor Applications - Köppel, Max; Podschus, Jasper; Joly, Nicolas Y.; Russell, Philip St. John; Schmauß, Bernhard (Optical Fiber Communication Conference, 2022)
Accurate tracking of optically levitated microparticles inside hollow-core photonic crystal fibers is a key requirement for novel “flying particle sensors”. We demonstrate a significantly improved tracking accuracy for accelerated particles by applying a Kalman filte
Keywords: Flying Particle Sensor; Fiber Sensing; Hollow-core Fiber

Kalman Filters - Theory for Advanced Applications - Pakala, Lalitha; Schmauß, Bernhard (Kalman Filters - Theory for Advanced Applications, 2018)
lhft_intern.bib::Pakala2018a

Karosserieaussenhaut mit integrierter Antenne - Fuchs, Manuel; Kilian, Andreas; Brocka, Zaneta; Schmachtenberg, Ernst; Schmidt, Lorenz-Peter (Kunststoffe, 2007)
UnivIS-Import:2015-03-09:Pub.2007.tech.IE.LEH.kaross

Klassifizierung koaxialer Mikrowellenantennen fuer die invasive Thermo-Radiotherapie - Erb, J; Engelbrecht, Rainer; Schaller, G; Klautke, G; Mueller, R; Seegenschmiedt, H; Sauer, R (1994)
lhft_intern.bib::thirty_years_LHFT_340

Klassifizierung koaxialer Mikrowellenantennen für die invasive Thermo-Radiotherapie - Erb, J.; Engelbrecht, Rainer; Schaller, Gerhard; Klautke, G.; Müller, R. G.; Seegenschmiedt, Heinrich; Sauer, R. (25. Wissenschaftliche Tagung der Deutschen Gesellschaft für Medizinische Physik (DGMP), 1994)
UnivIS-Import:2015-04-16:Pub.1994.tech.IE.LEH.klassi

Klimaentwicklung und Ozonabbau - Eine Herausforderung fuer die Erdfernerkundung - Brand, Hans (1994)
lhft_intern.bib::thirty_years_LHFT_336

Kombinierter Ultraschall-Mikrowellensensor für die zuverlässige Detektion von Anwesenheit und Bewegung - Vossiek, Martin; Ruser, H.; Magori, V.; Tränkler, H.-R. (8. Internationale Fachmesse mit Kongress für Sensoren, Messaufnehmer & Systeme, Sensor 97, 1997)
UnivIS-Import:2015-04-16:Pub.1997.tech.IE.LEH.kombin

Kommerzielles Radar-Imaging - Vossiek, Martin (BMBF-Workshop Fortgeschrittene Systemtechnologien und Verfahren zur Beurteilung bewegter 3D-Szenarien, 2002)
UnivIS-Import:2015-04-16:Pub.2002.tech.IE.LEH.kommer

Kommunikation in Technik-Wissenschaften oder: Was Ingenieure auerdem Fachlichen sonst noch wissen muessten und koennen sollten - Brand, Hans (Shaker Verlag, 2012)
lhft_intern.bib::Brand2012

Kompensation von Signalstörungen durch Intrakanaleffekte mit Hilfe symmetrischer Links - Striegler, Arne; Schmauß, Bernhard (5. ITG Fachtagung Photonische Netze, Leipzig, Mai, 2004)
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.kompen

Kontaktlose, bildgebende Untersuchung historischer Dokumente im Terahertz-Frequenzbereich - Ullmann, Ingrid; Schür, Jan; Root, Konstantin; Vossiek, Martin (Jahrestagung der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) 2022, 2022)
Bei der Untersuchung historischer Schriften ist es häufig nicht möglich oder erwünscht, die empfindlichen Dokumente zu öffnen, da das Risiko einer Beschädigung zu hoch ist. Zur kontaktlosen Inspektion solcher Dokumente kann die Röntgen-Technologie eingesetzt werden, allerdings einhergehend mit hohen Anforderungen an die Betriebssicherheit und einem potentiellen Beschädigungsrisiko für die zu untersuchenden Dokumente. Hier kann die Terahertz-Technologie eine interessante Alternative sein. Aufgrund der nicht-ionisierenden Strahlung und der geringen Leistungspegel gilt sie als unbedenklich, sowohl für Menschen als auch für historische Dokumente. Da Terahertz-Wellen die Eigenschaft besitzen, nichtleitfähige Materialien (u.a. Papier) zu durchdringen, besitzen Terahertz-Radarverfahren ein großes Potenzial zur berührungslosen und bildgebenden 3D-Darstellung von historischen Dokumenten. Im Gegensatz zum Seitenmaterial beinhalten historische Tinten häufig leitfähige oder stark verlustbehaftete Partikel, welche einen Bildkontrast zum Seitenmaterial bilden. Aufgrund der kurzen Wellenlängen sind mit Terahertz-Bildgebung Bildauflösungen im Sub-Millimeterbereich möglich. Die Terahertz-Technik wird daher bereits in vielfältigen Anwendungen im Bereich des Kulturerbes eingesetzt, beispielsweise zur Untersuchung historischer Gemälde. Die Untersuchung historischer Schriften mit Terahertz-Technologie ist dagegen noch ein relativ wenig beforschtes Gebiet. In diesem Beitrag werden verschiedene Mess- und Auswertemethodiken zur kontaktlosen Untersuchung historischer Dokumente mit Terahertz-Bildgebung vorgestellt und diskutiert: · Reflexions- und Transmissionsmessungen, · physikalische und synthetische Fokussierung, · Kurzpuls- und Dauerstrichverfahren. Der Beitrag zeigt aktuelle Forschungsergebnisse mit den verschiedenen Messmodalitäten. Im Fokus stehen zudem verschiedene Bildrekonstruktionstechniken. Die Eignung der Terahertz-Bildgebung zur Abbildung einlagiger und mehrlagiger Schriften wird diskutiert. Eine weitere Anwendung stellt die Abbildung historischer Schriftrollen dar, welche aufgrund der zylindrischen Objektgeometrie besondere Anforderungen an die Messgeometrie stellen. <

Large-Signal RF Circuit Model for a High-Power Laser Diode Module - Engelbrecht, Rainer; Groh, Jannis; Stumpf, Christopher; Adametz, Julian; Schmauß, Bernhard (IEEE Photonics Technology Letters, 2014)
An electrical large-signal circuit model for a 30-W high-power laser diode module is presented. Such modules are designed primarily for continuous wave (cw) operation but can be pulsed in the sub-μs temporal range for special applications. Our model is thus valid up to 20 MHz in the electrical frequency domain. The elements of the circuit model have been derived from RF impedance measurements using a calibrated vector network analyzer and a high-current dc/RF bias-T. The impedance is dominated by the inductance of the high-current connecting leads from the laser driver to the laser chip. The skin effect has been found to influence considerably both resistive and inductive impedances at high frequencies. For large-signal circuit simulations in the time domain, the current-voltage characteristic of the diode p-n junction is included by an analytic equation. The model is verified by comparison of simulation results with measured currents, voltages, and laser powers in large-signal pulsed-mode operation. This model is well suited for the design of optimized pulsed-current driver circuits. © 1989-2012 IEEE.
UnivIS-Import:2015-03-09:Pub.2014.tech.IE.LEH.larges
Keywords: Circuit modeling; Equivalent circuits; High-power laser diode; Impedance measurement; Large-signal; Optical pulses; Parameter extraction; Radio-frequency; Simulation

Laser in der Elektronikproduktion & Feinwerktechnik - LEF 2010 - Siekiera, A; Engelbrecht, Rainer; Bauer, R; Rehner, R; Schmauß, Bernhard (Laser in der Elektronikproduktion & Feinwerktechnik - LEF 2010, 2010)
lhft_intern.bib::siekiera10a

Laser-Sintering of Cyclic Olefine Copolymer for Low Dielectric Loss Applications - Romeis, Manuel; Ehrngruber, Michael; Drummer, Dietmar (Polymers, 2024)
With increasing demands for data transfer, the production of components with low dielectric loss is crucial for the development of advanced antennas, which are needed to meet the requirements of next-generation communication technologies. This study investigates the impact of a variation in energy density on the part properties of a low-loss cyclic olefin copolymer (COC) in the SLS process as a way to manufacture complex low-dielectric-loss structures. Through a systematic variation in the laser energy, its impact on the part density, geometric accuracy, surface quality, and dielectric properties of the fabricated parts is assessed. This study demonstrates notable improvements in material handling and the quality of the manufactured parts while also identifying areas for further enhancement, particularly in mitigating thermo-oxidative aging. This research not only underscores the potential of COC in the realm of additive manufacturing but also sets the stage for future studies aimed at optimizing process parameters and enhancing material formulations to overcome current limitations.
CRIS-Team Scopus Importer:2024-07-12
Keywords: additive manufacturing; COC; cyclic olefine copolymer; low dielectric loss; selective laser sintering; SLS

Latency measurement of 100 km fiber using correlation-OTDR - Azendorf, Florian; Dochhan, Annika; Schmauß, Bernhard; Eiselt, Michael (Photonische Netze - 20. ITG-Fachtagung, 2020)
By means of C-OTDR (Correlation - Optical Time Domain Reflectometry), we measured the latency of 100 km fiber with an accuracy of a few picoseconds. Based on iterating 49 measurements, we calculated a standard deviation of 12 ps between the round-trip latency values. To verify the reflection measurements, we used a single pass setup without reflector, which showed a maximum difference of only 11 ps.
CRIS-Team Scopus Importer:2021-04-19
Keywords: Fiber characterization; Latency; Optical Time Domain Reflectometry; Propagation delay

Lattice-Like Waveguides With Integrated Bragg Gratings in Planar Cyclic Olefin Copolymers - Kefer, Stefan; Pape, Natalie; Bischoff, Kay; Schmauß, Bernhard; Hellmann, Ralf (Journal of Lightwave Technology, 2024)
This contribution demonstrates femtosecond laser direct writing of lattice-like waveguides in planar cyclic olefin copolymer substrates. Based on numerical simulation and experimental near-field analysis, stable single-mode waveguiding around wavelengths of 1550 nm is demonstrated. The waveguiding mechanism is based on a hexagonal array of laser-induced, positive refractive index modification lines. Thus, the lateral extension of the guided mode can be adapted by varying the fabrication parameters and, in consequence, the resulting cross-sectional arrangement of the refractive index perturbations. With an optical attenuation of 2.2 dB·cm-1 around 1550 nm, the fabricated waveguides are well-suited for on-chip integrated photonic devices. Moreover, the waveguides can also be equipped with Bragg gratings to enable the application of the photonic platform as a sensing device. Depending on their length, the Bragg grating structures exhibit reflectivities of up to 99% and spectral widths down to 0.3 nm. The flexibility of the fabrication process and the sensing capabilities of the lattice-like waveguides with integrated Bragg gratings are underlined by an exemplary application study demonstrating a relative pressure sensor. For that, a photonic platform is micromilled to generate a 300 μm thick diaphragm and a reference pressure chamber. The strain introduced to the diaphragm by external pressure changes can then be quantified by the integrated photonic structures. This way, absolute pressure sensitivities of up to 38 pm·kPa-1 can be achieved in a relative pressure range from -60 to 100 kPa. The newly-developed lattice-like waveguides with integrated Bragg gratings are therefore well-suited for the realization of novel and adaptable photonic devices and sensors.
CRIS-Team Scopus Importer:2024-11-01
Keywords: Bragg grating; cyclic olefin copolymer; femtosecond laser; integrated photonics; lattice-like waveguide; pressure sensor

LFID: A passive light frequency identification system - Urban, Alexander; Kirsch, Fabian; Proebstl, Frank-Joachim; Vossiek, Martin (Sensoren und Messsysteme 2010, 2010)
lhft_intern.bib::Urban2010

Light Spot Hydrophone, Innovation in Lithotripsy - Granz, B.; Nanke, R.; Fehre, J.; Pfister, T.; Engelbrecht, Rainer (Medical Solutions, 2004)
UnivIS-Import:2015-03-09:Pub.2004.tech.IE.LEH.lights

Lineselective CO_2 Lasers with Anisotropic Etched Silicon Gratings - Schulz, R.; Hagen, J.; Schmidt, Lorenz-Peter (Conference on Lasers and Electrooptics 23.-27. 06.2003, München, 2003)
UnivIS-Import:2015-04-16:Pub.2003.tech.IE.LEH.linese

Lineselective CO_2 Lasers with Apodized-Littrow-Gratings - Hocke, R; Brand, Hans; Collischon, M; Schwider, J (1998)
lhft_intern.bib::thirty_years_LHFT_415

Lineselective CO_2-Lasers with Variable Line-Spacing and Variable Reflectivity Silicon Gratings - Schulz, R.; Collischon, M.; Brand, Hans; Schmidt, Lorenz-Peter (XV International Symposium on Gas Flow and Chemical Lasers, Prag, September, 2004)
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.linese

Lineselective CO 2 -lasers with variable line-spacing and variable reflectivity silicon gratings - Schulz, R; Collischon, M; Brand, Hans; Schmidt, Lorenz-Peter (XV International Symposium on Gas Flow and Chemical Lasers, Prag, September, 2005)
A lineselective CO2-laser with an unstable resonator is presented. The CO2-laser is realised with an rf-excited slab geometry to get a compact design with high output power. As lineselective element a grating in Littrow mount is used. The gratings are manufactured by anisotropic etching of silicon. The grating has a variable duty cycle to obtain a variable reflectivity. Furthermore, gratings are presented that have focusing propteries by a variation of the grating periodicit
lhft_intern.bib::schulz04a

Line shape of near infrared DFB and VCSEL diode lasers under the influence of back reflections - Lins, Bastian; Engelbrecht, Rainer; Zinn, P.; Buchtal, R.; Schmauß, Bernhard (8th International Conference on Tunable Diode Laser Spectroscopy, TDLS 2011, 2011)
UnivIS-Import:2015-04-16:Pub.2011.tech.IE.LEH.linesh

Line shapes of near-infrared DFB and VCSEL diode lasers under the influence of system back reflections - Engelbrecht, Rainer; Lins, Bastian; Zinn, P.; Buchtal, R.; Schmauß, Bernhard (Applied Physics B-Lasers and Optics, 2012)
Laser diode line widths and line shapes are experimentally investigated in dependence on the diode current and on back reflections from an optical system. Four distributed-feedback (DFB)-type diode lasers and two vertical-cavity surface-emitting lasers (VCSELs) have been tested within the same optical setup and using the same fitting methods. System back reflection ratios of light reflected back to the laser have been varied between -1 dB and -45 dB and were below -60 dB when all reflections were blocked. The background of this investigation is the evaluation of different laser types with respect to their suitability for sensor applications in which optical back reflections may occur, for example tunable diode-laser spectroscopy (TDLS). While DFB-type lasers showed almost pure Lorentzian line shapes and line widths of a few MHz, the tested VCSELs had a strong Gaussian contribution to the line shape, indicating stronger 1/f noise, which was also observed in the relative intensity noise of these particular lasers. System reflection ratios above -25 dB had strong effects on the line width in both DFB diode lasers and VCSELs, while some influences have been observed at even lower reflection ratios for DFB diode lasers. As much smaller reflection ratios are typically required in TDLS systems to avoid etalon-like fringes and self-mixing interference effects, we conclude that the influence on the line width is not the most important reason to minimize back reflections in practical TDLS systems or to choose one type of diode laser over the other. © 2012 Springer-Verlag.
UnivIS-Import:2015-03-09:Pub.2012.tech.IE.LEH.linesh

Localization of Backscatter Transponders Based on a Synthetic Aperture Secondary Radar Imaging Approach - Max, Stephan; Gulden, Peter; Vossiek, Martin (5th IEEE Workshop on Sensor Array and Multi-Channel Signal Processing (SAM 2008), 2008)
In this paper, we introduce the novel synthetic aperture secondary (SAS) radar positioning technique for the localization of a vehicle. The SAS technique is based on a frequency-modulated continuous wave (FMCW) secondary radar concept where the interrogating radar signal is reflected coherently by a backscatter transponder. It will be shown that SAS positioning is a very efficient way to combine the data of wireless positioning systems with the data from assisting sensors. Our novel SAS local positioning technique outperforms the usual integrated or hybrid navigation approaches based on multilateration notably. A 5.8-GHz wireless local positioning system has been built to test our SAS concept. The synthetic aperture is set up by a moving vehicle. Aperture points are determined with the use of gyroscope and tachymeter sensor data. A newly developed SAS reconstruction algorithm estimates the most likely transponder positions. Based on these estimations, the vehicle determines its position with an accuracy of approximately 5 cm even in complex multipath environments. © 2008 IEEE.
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.locali

Localization of Standard Compliant Passive RFID Transponders - Miesen, Robert; Kirsch, Fabian; Vossiek, Martin (RFIC 2013 Workshop on Radio Frequency Systems for Indoor Localization, 2013)
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.locali

Logarithmic Step-Size based Digital Backward Propagation in N-channel 112 Gbit/s/ch DP-QPSK Transmission, Stockholm, Sweden - Asif, Rameez; Lin, Chien-Yu; Holtmannspötter, Michael; Schmauß, Bernhard (IEEE ICTON Conference, 2011)
We propose and numerically investigate logarithmic step-size distribution for implementing efficient digital backward propagation (DBP) algorithm using split-step Fourier method (SSFM). DBP is implemented in N-channel 112Gbit/s/ch dual-polarization quadrature-phase-shift-keying (DP-QPSK) transmission over 2000km standard single mode fiber (SMF) with no in-line optical dispersion compensation. This algorithm is compared with constant step-size modified DBP (M-SSFM) algorithm in terms of efficiency, complexity and computational time. Furthermore, we investigate the same-capacity and same-bandwidth-efficiency transmission systems with 28GBaud and 56GBaud per-channel rates. The logarithmic step-size based DBP algorithm depicts efficient mitigation of chromatic dispersion (CD) and non-linear (NL) impairments. Benefit of the logarithmic step-size is the reduced complexity and computational time for higher baud rates.
lhft_intern.bib::Asif11

Logarithmic vs. modified digital backward propagation algorithm in224Gbit/s DP-16QAM transmission over dispersion uncompensated fiberlinks - Asif, Rameez; Lin, Chien-Yu; Schmauß, Bernhard (Optical Engineering, 2012)
lhft_intern.bib::Asif2012d

Long-Term Observations in Endoscopic Laser Coagulations in the Gastrointestinal Tract - Fruehmorgen, P; Kaduk, B; Reidenbach, H; Bodem, F; Demling, L; Brand, Hans (Endoscopy, 1975)
fter successful experiments on autopsy specimens and acute experiments in cats (4), we have now carried out a long-term study in dogs to establish whether, subsequent to light coagulations with the argon-ion laser in the oesophagus, stomach, small and large intestines, late morphological sequelae occur which are not observable in the acute experiments. For these light coagulations effected through a fibre-endoscope, a photo-coagulation system specially developed by us for this purpose and employing a fully-flexible plastic lightguide was used. Using various organ-orientated output powers and application durations, lesions of varying depth, together with coagulation zones were produced which, like peptic ulcers or erosions, healed within 12 to 24 days leaving behind a scar. Complications, in particular perforations, were not observed in any of the total 116 coagulations with the laser beam. The advance over electrocoagulation achieved with the laser beam is evident and is discussed. Our photocoagulation-system has been successfully applied in operative endoscopy to patients since June 197
lhft_intern.bib::thirty_years_LHFT_25

Low complexity logarithmic step-size based filtered digital backwardpropagation for compensating fiber transmission impairments - Asif, Rameez; Lin, Chien-Yu; Holtmannspötter, Michael; Schmauß, Bernhard (SPIE 8284, 82840Q, 2012)
lhft_intern.bib::Asif2012

Low Cost Colour Imaging of the Retina for Non-industrialized Countries - Höher, Bernhard; Voigtmann, Peter; Michelson, Georg; Schmauß, Bernhard (2014)
lhft_intern.bib::Hoeher2014a

Low Cost Fundus Camera-System for Telemedical Applications - Höher, Bernhard; Schmauß, Bernhard; Michelson, G. (World Ophthalmology Congress 2012, 2012)
lhft_intern.bib::Hoeher2012

Low-Cost Jamming System Against Small Drones Using a 3D MIMO Radar Based Tracking - Multerer, Thomas; Ganis, Alexander; Prechtel, Ulrich; Miralles, Enric; Meusling, Askold; Mietzner, Jan; Vossiek, Martin; Loghi, Mirko; Ziegler, Volker (14th European Radar Conference EuRAD, 2017)

Low-Cost Sensitive Liquid Level Monitoring Using Polymer Optical Fibers - Bär, Matthias; Werzinger, Stefan; Köppel, Max; Schmauß, Bernhard (26th International Conference on Plastic Optical Fibres (POF2017), 2017)
lhft_intern.bib::Baer2017a

Low-Frequency RF-Excitation of CO_2-Laser - Heller, F; Jirmann, J; Brand, Hans (1989)
lhft_intern.bib::thirty_years_LHFT_263

Low-Loss Frequency Selective Surfaces on Silicon Substrates for Sub-millimeter Wave Applications - Biber, Stephan; Bozzi, M.; Günther, O.; Perregrini, L.; Schmidt, Lorenz-Peter (Symposium on Antennas and Propagation, Washington DC, July, 2005)
A new class of frequency selective surfaces (FSSs), to be used as quasi-optical filters for harmonic suppression in sub-mm wave frequency multipliers, is proposed and experimentally verified. The FSSs consist of two-dimensional aperture arrays, and are made from microstructured aluminium on electrically thick, high-resistivity silicon substrates. This leads to a very good mechanical stability, low insertion loss, and permits to manufacture the structure by using standard processes available from the semiconductor industries. This paper presents the design, fabrication, and testing of two sets of prototypes, the former with a pass-band at 300 GHz and a stop-band at 450 GHz and the latter with a pass-band at 600 GHz and a stop-band at 750 GHz. © 2005 IEEE.
UnivIS-Import:2015-04-16:Pub.2005.tech.IE.LEH.lowlos

Low Loss Printable Dielectrics for mmWave Components - Panusch, David; Romeis, Marcus; Gold, Gerald (EuCAP 2025 - 19th European Conference on Antennas and Propagation, 2025)
In this paper, a comprehensive list of materials in combination with various additive manufacture (AM) approaches is provided to facilitate the optimal selection of low-loss dielectric materials. As a case study for those AM low loss materials an additively manufactured dielectric tripole rod antenna with integrated multimode power divider is presented. The demonstrator itself has a bandwidth of B20dB≈ 4.7 GHz at a center frequency of fc=75 GHz.
CRIS-Team Scopus Importer:2025-06-20

Low Loss Silicon Window Material for Submillimeter Waves Using Micromachined Artificial Dielectrics for Anti-Reflection Coating - Biber, Stephan; Schneiderbanger, Dirk; Schmidt, Lorenz-Peter (29th International Conference on Infrared and Millimeter Waves , September, 2004)
A high-resistivity silicon wafer was used to design a broad-band low loss window material for 600GHz by micromachining an artificial dielectric as a quarter wave transformer on the front and rear side of the wafer. The artificial dielectric is made from a 2-dimensional periodic structure to ensure the same transmission characteristics for horizontally and vertically polarized waves. © 2004 IEEE.
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.lowlos

Low Profile LTCC Balanced Filter Based on a Lumped Elements Balun for WiMAX Applications - Sakhnenko, Sergiy; Orlenko, Denys; Markov, Konstyantyn; Yatsenko, Andriy; Vorotnikov, Borys; Sevskiy, Georgiy; Heide, Patric; Vossiek, Martin (IEEE International Microwave Symposium 2008, 2008)
This paper reports on a design of a balanced filter based on a new lumped LC type balun. The realization disadvantages of conventional LC baluns integrated In a front-end module have been discussed and a new low profile lumped-element balun has been proposed. The balanced filter is realized as a combination of a second order band pass filter and the novel LC balun with an additional low-pass circuit. The proposed layout has been realized using multilayer low temperature co-fired ceramic (LTCC) technology. The resulting structure exhibits excellent electrical performance, immunity to manufacturing tolerances and compactness. The realized low profile balanced Alter is placed between two ground planes ensuring high electromagnetic compatibility which allows using this balanced filter as a building block of highly integrated WiMAX front-end modules. © 2008 IEEE.
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.lowpro
Keywords: Balanced filter; Balun; Front-end module; LTCC; WiMAX

Low reflective aerosol Jet printed broadband matched load up to 67 GHz - Lomakin, Konstantin; Sippel, Mark; Gold, Gerald; Fröhlich, Jan; Helmreich, Klaus; Ankenbrand, Markus; Franke, Jörg (German Microwave Conference, 2018)
This work presents an additively manufactured termination circuit in terms of a microstrip transmission line with gradually varying conductivity applicable up to 67 GHz with an absolute reflection coefficient of less than −10 dB — and even less than −15 dB above 12 GHz. Different load conditions and manufacturing approaches are discussed and a time domain analysis supporting the design is presente

Machine Learning Assisted Fiber Bragg Grating-Based Temperature Sensing - Djurhuus, Martin S. E.; Werzinger, Stefan; Schmauß, Bernhard; Clausen, Anders T.; Zibar, Darko (IEEE Photonics Technology Letters, 2019)
This letter proposes an alternative approach to the signal processing of temperature measurements based on fiber Bragg gratings (FBGs) using the machine learning tool Gaussian process regression (GPR). The experimental results show that for a majority of the cases under consideration, the reported technique provides a more accurate calculation of the temperature than the conventional methods. Furthermore, the GPR can give the uncertainty of an estimate together with the estimate itself, which for example is useful when it is important to know the worst-case scenario of a measurand. The GPR also has the potential to improve the measurement speed of FBG-based temperature sensing compared to current standards.
CRIS-Team WoS Importer:2019-06-18

Machine learning assisted fibre Bragg grating based temperature sensing - Djurhuus, M; Werzinger, Stefan; Schmauß, Bernhard; Clausen, A; Zibar, Darko (International Conference on Optical Fibre Sensors (OFS), 2018)

Magnetically Enhanced Ultrasound Strain Elastography to Visualize Magnetic Nanoparticles - Huber, Christian; Müller, Melina Sophie; Ermert, Helmut; Heim, Christian; Rupitsch, Stefan J.; Ullmann, Ingrid; Lyer, Stefan (22. GMA/ITG-Fachtagung Sensoren und Messsysteme 2024, 2024)
This study explores the potential of Magnetically Enhanced Ultrasound Strain Elastography (MUSE) for visualizing the distribution of magnetic nanoparticles (MNPs) employed in magnetic drug targeting (MDT). MDT leverages MNPs as drug carriers, accumulated by an external magnetic field at the target site, typically a tumor. The localized accumulation of these particles alters the effective elastic properties of the tissue, potentially enabling visualization through ultrasound strain imaging, which maps local variations in elasticity. However, a direct link between MNPs and regions of increased stiffness has yet to be established. This work proposes MUSE as a solution, utilizing an external magnetic field to manipulate MNP distribution and consequently, tissue elasticity. The feasibility of MUSE was assessed using a polyvinyl alcohol ultrasound phantom containing an MNP inclusion. The results demonstrated successful mapping of the inclusion using the proposed metho
Keywords: Medical Technology; Ultrasound Imaging; Cancer Therapy; Magnetic Nanoparticles; Magnetic Durg Targeting

Magnetically Tunable Filter from 72 GHz to 95 GHz - Sterns, M.; Hrobak, M.; Martius, Siegfried; Schmidt, Lorenz-Peter (5th German Microwave Conference, 2010)
In this paper a magnetically tunable filter based on unilateral finlines is presented. The filter covers a tuning frequency range from 72 GHz to 95 GHz, achieving an insertion loss between 11.3 dB and 7.3 dB.
lhft_intern.bib::sterns10

Magnetically Tunable Hexaferrite Bandpass Filter from 43 GHz to 83.5 GHz - Sterns, Michael; Rehner, Robert; Schneiderbanger, Dirk; Martius, Siegfried; Schmidt, Lorenz-Peter (Proceedings of the 39th European Microwave Conference, 2009)
In this paper a novel magnetically tunable bandpass filter based on open-ended unilateral finlines is presented. The filter covers a tuning frequency range from 43 GHz to 83.5 GHz with a typical insertion loss between 6.7 dB and 8.5 dB. Hexaferrite resonators are used to obtain high resonant frequencies with comparatively low magnetic field strengths. Although only two resonators are used, an off resonance isolation of about 60 dB is achieved. In the cutoff region of the finlines the filter exhibits an off resonance isolation of more than 80 dB. The use of unilateral finlines as coupling lines simplifies the integration of the filter into a planar transmission line environment what is advantageous for the design of integrated high frequency modules. Further on, a considerably larger operating frequency range is covered, compared to classical rectangular waveguide based concepts.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.LEH.magnet

Magnetomotive Displacement of Magnetic Nanoparticles in Different Tissue Phantoms - Huber, Christian; Heim, Christian; Li, Jiaqi; Ermert, Helmut; Rupitsch, Stefan J.; Ullmann, Ingrid; Lyer, Stefan (Current Directions in Biomedical Engineering, 2024)
Magnetic nanoparticles (MNPs) can be used invarious biomedical applications, such as magnetic drug tar-geting (MDT) or magnetic hyperthermia for cancer treatment.MNPs are injected into the body and accumulated with anexternal magnetic field at the tumor site. For therapy mon-itoring, the MNPs distribution has to be accurately mappedin real time. Magnetomotive ultrasound (MMUS) is a suit-able technique for this purpose. It was already demonstratedthat MMUS can map the accumulation process of MNPs dur-ing MDT. Moreover, inverse MMUS is an advanced techniqueto quantify MNP distribution. This method simulates the dis-placement of MNPs and surrounding tissues and compares theresults to measured data. Understanding how magnetomotivedisplacement behaves in various elastic environments is cru-cial for advancing inverse MMUS and accurately quantifyingMNP distributions. In this study, ultrasound tissue phantomswere fabricated with varying elastic parameters, incorporatingMNPs. Subsequently, their MMUS displacement is assesse
Keywords: Ultrasound Imaging; Displacement Tracking; Magnetic Nanoparticles; Magnetic Drug Targeting

Markerless RGB-D Hand Pose Estimation for Activity Monitoring of Musculoskeletal Diseases - Wirth, Vanessa; Liphardt, Anna-Maria; Coppers, Birte; Bräunig, Johanna; Heinrich, Simon; Leyendecker, Sigrid; Kleyer, Arnd; Schett, Georg; Vossiek, Martin; Egger, Bernhard; Stamminger, Marc (IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI’23), 2023)

Mean and Differential Phase Centers of Rectangular Dielectric RodAntennas - Richter, J; Garbas, Jens-Uwe; Schmidt, Lorenz-Peter (2004)
lhft_intern.bib::richter04a

Mean and Differential Phase Centers of Rectangular Dielectric Rod Antennas - Richter, Jürgen; Garbas, Jens-Uwe; Schmidt, Lorenz-Peter (Proceedings of the European Microwave Conference, 2004)
Dielectric rod antennas of rectangular cross section are of increasing interest at millimeterwave frequencies. For many applications like e.g. densely packaged feed arrays for reflector/lens systems or electromagnetic field probes the exact knowledge of the phase center location is required. This paper will describe two efficient methods to determine the mean and differential phase center locations of such antennas by means of numerical electromagnetic field simulations and a subsequent analysis of the computed antenna phase pattern. Phase center locations of various dielectric rod antennas with rectangular cross section are presented and the influence of geometrical parameters and frequency on the phase center location are analyzed and discussed in detail. The theoretically derived results are also compared to measurements performed at X-band frequencies.
UnivIS-Import:2015-03-09:Pub.2004.tech.IE.LEH.meanan

Measurement of Phase Centers of Rectangular Dielectric Rod Antennas - Richter, Jürgen; Müller, matthias; Schmidt, Lorenz-Peter (IEEE International Antennas and Propagation Symposium, Monterey, California, 2004)
Dielectric rod antennas of rectangular cross section are of increasing interest at miliimeterwave frequencies. For many applications like e.g. densely packaged feed arrays for reflector/lens systems or electromagnetic field probes the exact knowledge of the phase center location is required. This paper will describe a simple experimental method to determine the phase center of antennas by means of a phase pattern measurement and a numerical least square fit procedure. For feed antennas the method can be adopted to the numerical aperture of reflector or lens systems. Phase center locations of various dielectric rod antennas with rectangular cross section are presented and the influence of geometrical parameters and frequency on the phase center are analysed and interpreted in detail.
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.measur_5

Measurement of Stimulated Brillouin Scattering Dynamics in Raman Fiber Amplifiers - Engelbrecht, Rainer; Küch, Karsten; Hagen, Johannes; Schmauß, Bernhard (Europhoton 2006, Pisa, 10.-15. Sept., 2006)
UnivIS-Import:2015-04-16:Pub.2006.tech.IE.LEH.measur

Measurement of Stimulated Brillouin-Scattering suppression in well-defined strained fibers for high-power fiber lasers and amplifiers - Engelbrecht, Rainer; Hagen, Johannes; Schmidt, Matthias (EPS-QEOD Europhoton Conference on Solid-State and Fiber Coherent Light Sources, 29 August - 3 September, Lausanne, Switzerland, 2004)
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.measur

Measurement of Trace Gases in Sealed-off CO_2 Lasers with Tunable Diode Lasers in the Near Infrared - Engelbrecht, Rainer; Hocke, Ralf; Brand, Hans (ITG-Fachbericht 150 (8th ITG-Conference on Displays and Vakuum Electronics, Garmisch-Partenkirchen 1998), 1998)
UnivIS-Import:2015-04-16:Pub.1998.tech.IE.LEH.measur

Measurement Setup for Non-Destructive Complex Permittivity Determination of Solid Materials Using Two Coupled Coaxial Probes - Cenanovic, Amir; Schramm, Marcus; Schmidt, Lorenz-Peter (IMS 2011, 2011)
A non-destructive microwave measurement setup for broadband complex permittivity determination of solid materials over a frequency band from 0.05 GHz to 6 GHz is presented. The setup design was optimized for measurements of glass materials with planar and convex surfaces, but works with other dielectric materials as well. The measurement method is based on the near field coupling of two open-ended coaxial probes through the material under test (MUT). A theoretical modeling of this measurement configuration was performed, using a 3D full-wave electromagnetic field simulator. Two identical coaxial probes and an equivalent calibration kit, in order to perform a TRL calibration of the proposed setup, were designed. The calibration procedure of the measurement setup is explained and experimental results are presented.
lhft_intern.bib::Cenanovic11a

Measuring Design-DK and True Permittivity of PCB Materials up to 20 GHz - Gold, Gerald; Helmreich, Klaus (Proceedings of the 9th German Microwave Conference (GeMiC2015), 2015)
Many measurement methods for dielectric properties are influenced by surrounding conductor structures, which is especially significant in the case of copper cladded PCB materials. The paper explains the reasons for this, shows how to interpret data sheet values and introduces a measurement assembly and method that allows for precise determination of true relative permittivity and loss tangent. The presented assembly is customized for thin PCB material.
UnivIS-Import:2015-10-26:Pub.2015.tech.IE.c3scha.measur

Measuring Dielectric Properties of PCB Material in the Two-Digit GHz-Range - Gold, Gerald; Helmreich, Klaus (Abstract Book, 2013)
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.c3scha.measur

Measuring Signal Integrity - Helmreich, Klaus (IEEE Microwave Magazine, 2011)
lhft_intern.bib::Helmrich2011

Mechanical performance evaluation of fiber composites equipped with In-Situ wireless sensor bodies - Dutta, Gaurab Sundar; Ziegmann, Gerhard; LI, Wanlu; Dorbath, Benedikt; Vossiek, Martin; Guhathakurta, Jajnabalkya (Tagungsband 5. Niedersächsisches Symposium Materialtechnik, 2023)
Key objective here was to optimize the sensor shape to minimize stress accumulation and crack propagation around the sensor geometry inside the cured composite sample understress. A finite element simulation model is developed for this purpose and a par- ametric model for the sensor geometry provided better insight into the force distribution along the fibers around the sensor element. Consequently, different testing sample combinations were prepared, for which, fibers were either cut or bend around the sensors and dielectric channels. Various composite samples with different shapes of sensor dummies were also experimentally tested to validate the computational results. CT scan models of postcure samples before and after loading enabled indepth understanding of fiber alignment that could cause disturbances in overall mechanical performance. The scan models also provided with sufficient information about unwanted porosity, and micro -crack growth inside the composite un- der loading, which turned out to be vital for establishing a reliable simulation model and improving parameters in manufacturing process. In the end, the goal of the work was to transport the know -how of such pro duction unit from experimental and flexible manufacturing system like vacuum assisted resin infu- sion (VARI) to more sophisticated processing systems like prepreg manufacturing where all necessary information can be provided as inputs prior to the impregnation, thus removing error occurred due to manual handling.

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2007 - Penne, J; Hoeller, K; Stuermer, M; Schrauder, T; Engelbrecht, Rainer; Feussner, H; Schmauß, Bernhard; Hornegger, J (Springer Berlin Heidelberg, 2007)
lhft_intern.bib::penne09

MEMSTIC - Eine neue Schaltungstechnologie fuer den Submillimeter-Wellenlängenbereich - Brand, Hans; Weinzierl, Jochen (Frequenz, 2000)
lhft_intern.bib::brand00

Merkblatt MTHz 01 - Mikrowellenprüfung: Grundlagen und Anwendungen - Becker, Stefan; Hinken, Johann H.; Schür, Jan (DGZfP Jahrestagung 2021 (Virtuell), May, Germany (DGZfP 2021), 2021)
Das neue Merkblatt Mikrowellenprüfung: Grundlagen und Anwendungen (MTHz 01) gibt erstmals einen Überblick über die Anwendung der Mikrowellen- und Millimeterwellenprüfung (im Frequenzbereich von 2 GHz bis 300 GHz) zur zerstörungsfreien Prüfung von Bauteilen aus elektrisch nichtleitenden Materialien. Es gibt die erforderlichen Informationen und Entscheidungsgrundlagen für mögliche Einsätze in der Entwicklung, der Fertigung und der Wartung. Das Merkblatt enthält neben einer komprimierten Erläuterung der naturwissenschaftlich-technischen Grundlagen auch die Beschreibung von Anwendungsfällen einschließlich der Durchführung der Prüfung und Angaben zur Gerätetechnik. Bei der Mikrowellenprüfung handelt es sich primär um ein Verfahren zur Erkennung von Defekten in elektrisch isolierenden, also dielektrischen Materialien und Bauteilen. Aber auch messtechnische Aufgaben lassen sich mit ihr lösen. Das Verfahren beruht auf der Ausbreitung, Reflexion und weiteren Wechselwirkungen zwischen Material und elektromagnetischer Wellen. Zu den prüfbaren Materialien gehören beispielsweise Kunststoffe, glasfaserverstärkte Kunststoffe (GFK), Kunststoffschäume und viele Arten von Keramik. Beispielsweise können Poren, Fremdmaterialeinschlüsse, sowie in GFK Delaminationen und Ondulationen detektiert werden. Wand- und Schichtdicken lassen sich ebenso messen. Die Mikrowellenprüfung benötigt kein Koppelmittel und kann berührend oder nichtberührend in Reflexions- oder Transmissionsverfahren eingesetzt werden. Anders als z.B. Röntgenstrahlen sind Mikrowellen nicht ionisierend und daher im Vergleich unbedenklich. Ihre Wirkung auf den Körper besteht im Wesentlichen in einer Erwärmung durch Absorption. Eine gesundheitsschädliche Wirkung kann durch eine Begrenzung der Temperaturerhöhung von typischerweise <1 Kelvin erreicht werden. Die dafür relevanten Grenzwerte für die Feldstärken der Mikrowellen werden bei gängigen mikrowellenbasierten ZfP-Verfahren weit unterschritte
Keywords: nondestructive Testing Microwave mmW

Messungen an bewegten Verkehrsobjekten mit einem 70-GHz-Echtzeit-Abbildungssystem (mit Video-Bild-Demonstration) - Gloeckler, R; Osterrieder, S; Brand, Hans (1983)
lhft_intern.bib::thirty_years_LHFT_162

Method for Characterization and Quantification of Radiation Characteristics of Microwave Antennas for Hyperthermia Treatment Planning - Erb, J.; Seegenschmiedt, Heinrich; Engelbrecht, Rainer; Schaller, Gerhard; Sauer, R. (Radiology 193(P), 227 (1994), Proceedings of RSNA/AAPM, 1994)
UnivIS-Import:2015-04-16:Pub.1994.tech.IE.LEH.method

Method for High Precision Clock Synchronization in Wireless Systems with Application to Radio Navigation - Röhr, Sven; Vossiek, Martin; Gulden, Peter (IEEE Radio Wireless Symposium, 2007)
In this paper we present a novel approach for high precision clock synchronization in wireless systems. A concept similar to the standard FMCW (Frequency-Modulated Continuous Wave) radar principle is used to estimate the offset in time and in frequency between two wireless communication units. The novel approach allows for a synchronization of both offsets significantly below 100 ps and 10 Hz, respectively. This highly accurate synchronization is used in a prototype system to measure the distance between wireless units similar to a secondary radar. The prototype works within the 5.8 GHz ISM-Band and uses a bandwidth of 150 MHz. With the setup presented we can measure the distance between two radio units with a standard deviation of 4 to 5 cm over a range of 200 m. This distance deviation implies a clock and center frequency synchronization of both communication modules significantly below 100 ps and 1 ppb, respectively. The broadband measurement principle is robust towards multi-path interference. It can be extended to other frequency bands and is well-suited for direct integration into communication channels and novel modulation principles such as OFDM (Orthogonal Frequency Division Multiplexing) or SC/FDE (Single Carrier transmission with Frequency Domain Equalization), e.g. for locatable WLAN (Wireless Local Area Network) devices or wireless sensor networks. ©2007 IEEE.
UnivIS-Import:2015-04-16:Pub.2007.tech.IE.LEH.method
Keywords: Radar distance measurement; Radar navigation; Radar position measurement; Synchronization

Method for High Precision Radar Distance Measurement and Synchronization of Wireless Units - Röhr, Sven; Vossiek, Martin; Gulden, Peter (IEEE MTT-S International Microwave Symposium, 2007)
In this paper we present a novel approach for high precision synchronization of wireless units. A concept similar to the standard FMCW (Frequency-Modulated Continuous Wave) radar principle is used to estimate the offset in time and in frequency between two radar units. It allows for a synchronization of both offsets significantly below 100 ps and 10 Hz, respectively. This highly accurate synchronization is used in a prototype system to measure the distance between wireless units similar to a secondary radar. The prototype operates within the 5.8 GHz ISM-Band and uses a bandwidth of 150 MHz. With the setup presented the distance between two radar units is measured with a standard deviation of less than 4 cm over a range of 250 m. The broadband measurement principle is robust towards multipath interference. It can be extended to other frequency bands and is well-suited for direct integration into communication channels. © 2007 IEEE.
UnivIS-Import:2015-04-16:Pub.2007.tech.IE.LEH.method_0
Keywords: Radar distance measurement; Radar navigation; Radar position measurement; Synchronization

Methods for Characterization and Quantification of Radiation Characteristics of Microwave Antennas for Hyperthermia Treatment Planning - Erb, J; Seegenschmiedt, R; Engelbrecht, Rainer; Schaller, G; Sauer, R (1994)
lhft_intern.bib::thirty_years_LHFT_372

Micromachined Split-block Schottky-Diode Mixer for 600 GHz - Schür, Jan; Biber, Stephan; Gumbmann, Frank; Mottet, B.; Cojocari, O.; Schmidt, Lorenz-Peter; Hartnagel, H. (29th International Conference on Infrared and Millimeter Waves, 2004)
This paper presents simulation results for a 600 GHz micro-machined waveguide mixer with integrated horn antenna, a hybrid-integrated planar Schottky diode and IF filter structures on a quartz substrate. In addition to the simulated electrical performance we will show first approaches for the manufacturing of the split-block mixer by both micro-mechanical milling and silicon etching technology. ©2004 IEEE.
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.microm

Micromilling-assisted fabrication of monolithic polymer ridge-type waveguides with integrated photonic sensing structures - Kefer, Stefan; Pape, Dominik; Roth, Gian-Luca; Hessler, Steffen; Schmauß, Bernhard; Hellmann, Ralf (Optical Materials Express, 2021)
This study demonstrates and discusses a novel approach for the fabrication and rapid prototyping of monolithic photonic platforms comprising a ridge-type waveguide with integrated sensing structures. First, the bulk injection-molded cyclic olefin copolymer substrates are micromilled in order to define the physical extension of the ridge structure. Cross-sections down to 30 × 30 μm2, exhibiting a mean surface roughness of 300 nm, are achieved with this process. Subsequently, UV radiation is used to modify the ridge structure's refractive index, which leads to the formation of an optical waveguide. By employing a phase mask, it is possible to equip the photonic platform with a Bragg grating suitable for temperature measurements with a sensitivity of -5.1 pm K-1. Furthermore, an integrated Fabry-Pérot cavity, generated during the micromilling step as well, enables refractive index measurements with sensitivities up to 1154 nm RIU-1.
CRIS-Team Scopus Importer:2021-08-13

Microwave Design Criteria for Quasi-Optical Terahertz Mixers - Brand, Hans; Brune, J; Siart, U (1995)
lhft_intern.bib::thirty_years_LHFT_364

Microwave excitation of a diffusion-cooled CO2 laser - März, Martin; Oestreicher, Wolfgang (Journal of Physics D: Applied Physics, 1994)
A microwave-excited (2.45 GHz), diffusion-cooled CO2 laser, capable of operating in a quasi-cw mode, has been developed. By separating the discharge structure from the feeding RF waveguide and using distributed coupling, previous problems with local contracting discharges could be surmounted. For effective diffusion cooling a planar 1.9 mm high discharge channel was used, a structure which easily allows area scaling of laser output power. Two discharge channel designs (metal/glass and all ceramic) were investigated, differing mainly in thermal conductivity and waveguide losses for the 10.6 mu m laser radiation. A conventional magnetron for microwave ovens was used as microwave source. System design and extensive measuring results are presented. With a first prototype non-optimized in gas mixture, optical resonator and waveguide surface quality laser output power above 20 W was obtained with an efficiency of about 10%. © 1994 IOP Publishing Ltd.
Created from Fastlane, Scopus look-up

Microwave Excitation of Diffusion-Cooled CO_2 Lasers - Oestreicher, W; Deuringer, J; Brand, Hans (1998)
lhft_intern.bib::thirty_years_LHFT_417

Microwave Imaging System Conditions of Different Applications - Brand, Hans (1983)
lhft_intern.bib::thirty_years_LHFT_157

Microwave Sensor Modules for Automotive Applications - Vossiek, Martin; Heide, Patric (IWPC Future Automotive Wireless Packaging Workshop, 2000)
UnivIS-Import:2015-04-16:Pub.2000.tech.IE.LEH.microw

Microwave Technology in the Terahertz Region - Brand, Hans (IEEE, 1991)
Electromagnetic waves with frequencies between 0.1 THz and some 10 THz cover the gap from the millimeter wave bands to the infrared optical region. Coherent microwave technology concerning signal generation and detection has been introduced in this THz-region to a steadily growing extent in the past, mainly forced by applications in radioastronomy and remote sensing. The paper tries to review the state of the art of this submillimeter wave technology with emphasis on molecular gas lasers as sources and quasi-optical waveguiding for signal processin
lhft_intern.bib::thirty_years_LHFT_289

Mikrowellenabbildung von schnell bewegten Verkehrsobjekten - Brand, Hans (1984)
lhft_intern.bib::thirty_years_LHFT_179

Mikrowellenbasiertes Prozessmonitoring von Aushärtungsvorgängen bei der Herstellung von GFK-Bauteilen - Groh, Jannis; Javdanitehran, M; Vossiek, Martin; Javdanitehran, Mehdi (3. Fachseminar Mikrowellen- und Terahertz-Prueftechnik in der Praxis, 2017)

Mikrowellen-Echtzeit-Abbildung durch Parallel Signalverarbeitung mit einem 9-GHz-Leitungsnetzwert - Brand, Hans; Koenig, G (1983)
lhft_intern.bib::thirty_years_LHFT_161

Mikrowellen-geschaltete Gasentladungen und ihre Anwendung beim CO2-Laser - Brand, Hans; März, M (Archiv fuer Elektrotechnik, 1996)
Der Artikel beschreibt ein neuartiges Verfahren zur Steuerung von Gasentladungen mittels Mikrowellen-Energie. Das vorgestellte Verfahren derMikrowellen/DC-Hybridanregung kombiniert die Stärken der Gleichspannungsanregung mit der einfachen Steuerbarkeit und der schnellen Pulsbarkeit HF-angeregter Entladungen. Anders als bei einer reinen HF-Anregung können durch die Verlagerung der Energiespeicherung auf die Gleichspannungsseite sehr kostengünstige Hochfrequenzquellen wie beispielsweise Küchenherd-Magnetrons eingesetzt werden; hochspannungsseitig besteht der Vorteil im Wegfall jeglicher Schalter im Entladungsstromkreis. Am Beispiel des CO2-Lasers wird gezeigt, wie mikrowellen/DC-hybridangeregte Laser realisiert werden können. Diese Laser lassen sich-gesteuert durch die Mikrowellenquelle-kontinuierlich zwischen einem Dauerstrichbetrieb und einem Pulsbetrieb mit hohen Pulsleistungsüberhöhungen betreiben, wobei ein dynamischer Wechsel zwischen den Betriebsarten innerhalb von Millisekunden möglich is
lhft_intern.bib::thirty_years_LHFT_392

Mikrowellenmodule, Systemkonzepte und Signalverarbeitung für innovative Radarsensoren - Vossiek, Martin; Nalezinski, Martin (EEEfCom Workshop, 2004)
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LEH.mikrow

Mikrowellentechnik auf dem Weg in die 90er Jahre - Brand, Hans (Archiv fuer Elektrotechnik, 1991)
In diesem Beitrag wird versucht, den Stand der Technik auf dem Gebiet der elektromagnetischen Mikrowellen zu Beginn der 90er Jahre zu umreißen. Darunter wird der Teil des Spektrums verstanden, bei dem die Wellenlänge λ mit den Linearabmessungen der Bauteile vergleichbar ist: er erstieckt sich von etwa λ=3 m (f=100 MHz) bis λ =300 μm (f=1000 GHz). Als Beispiele für Komponenten oder Subsysteme werden Mikrowellenröhren mit Mikrowellen-halbleitern zur Erzeugung hoher Leistungen verglichen und die Entwicklung auf dem Gebiete der Wellenleiter, Antennen und der Empfangssysteme betrachtet. Erkenntnisse über die Wellenausbreitung um den Planeten Erde waren wesentliche Voraussetzungen für die Erfolge der Satelliten-Funktechnik und bei Weltraumforschungsmissionen. Bei den Anwendungen wird die Radartechnik sowie die Radiometrie mit ihrer wachsenden Bedeutung für den Umweltschutz und schließlich eine eventuelle zukünftige drahtlose Energieübertragung besonders hervorgehobe
lhft_intern.bib::thirty_years_LHFT_280

Millimeter Wave Backscatter Transponders for Secondary Radar-Based Localization - Stein, Wadim; Carlowitz, Christian; Vossiek, Martin (IEEE Radio Wireless Week 2014, 2014)
UnivIS-Import:2015-04-16:Pub.2014.tech.IE.LEH.millim

Millimeter wave frontend concepts and MMICs for automotive and communicationapplications - Schmidt, Lorenz-Peter; Adelseck, B; Guettich, U (MTT-Symposium, Workshop „Wireless Applications“, 1994)
lhft_intern.bib::Schmidt32

Millimeter-wave imaging and near-field spectroscopy for burn wound assessment - Hecht, Damaris; Ullmann, Ingrid; Oppelt, Daniel; Pfahler, Tim; Amer, Nadia; Vossiek, Martin (Frequenz, 2022)
Diagnostic applications for skin in the microwave range have developed significantly in recent years, due the non-invasiveness of these applications and their ability to assess tissue water content. Despite their capabilities, however, there is still no appropriate clinically applicable microwave tool for the assessment of burn wounds. A common practice is the visual inspection and evaluation of burns by the doctor, which is a challenging task even for experienced medical professionals. An incorrect assessment can have far-reaching consequences, such as unnecessary surgery or surgery that is necessary but omitted. In this paper, two different approaches of millimeter-wave burn wound assessment are presented: millimeter-wave imaging and near-field spectroscopy. For imaging, a MIMO sparse array was used to assess ex vivo burns on porcine skin in the frequency range of 70-80 GHz. With a resonant millimeter-wave near-field probe, reflective spectroscopy at individual sites of an ex vivo burn on porcine skin in the frequency range of 75-110 GHz was performed. The results showed individual advantages and drawbacks for both approaches, with surprising benefits of the spectroscopic method. Nevertheless, both approaches were shown to be suitable for clinical usage in diagnosing burns.
CRIS-Team WoS Importer:2022-08-26
Keywords: burn injuries; millimeter-wave imaging; millimeter-wave spectroscopy; near-field probe; reflectometry

Millimeter-wave imaging concepts: Synthetic Aperture Radar (SAR) and Digital Beam Forming (DBF) - Gumbmann, Frank; Tran, Hue Phat; Cenanovic, Amir; Methfessel, Sebastian Dirk (Frequenz, 2009)
Short range radar imaging systems for various security and non-destructive testing (NDT) applications are mainly based on synthetic aperture radar (SAR) or digital beam forming (DBF) techniques. In this article the development of a real-time SAR and a real-time DBF system is presented. The goal is to achieve a 3D image of a large measurement area with a high lateral and range resolution in order to detect suspicious items or material approach. This can be realized with a SAR system which is based on a new rotating virtual antenna concept. Another approach is a digital beam forming concept consisting of spatially distributed transmitters and receivers. Experimental results on specific test objects are presented to prove the performance of both concepts.
UnivIS-Import:2015-03-09:Pub.2009.tech.IE.LEH.millim
Keywords: Digital beam forming; Millimeter-wave imaging; Synthetic aperture radar

Millimeter-Wave Imaging With Optimized Sparse Periodic Array for Short-Range Applications - Gumbmann, Frank; Schmidt, Lorenz-Peter (IEEE Transactions on Geoscience and Remote Sensing, 2011)
lhft_intern.bib::Gumbmann2011

Millimeter-Wave Monolithic Integrated Circuits - Schmidt, Lorenz-Peter; Menzel, W; Adelseck, B; Guettich, U (International MMIC-Workshop ESA/ESTEC, 1986)
This paper summarizes the progress, trends, and technical issues associated with monolithic millimeter-wave integrated circuit technology. Presented first is background information which sets forth a description of the opportunities which spur this activity, and a summary of the important technical challenges. The technical challenges encompass aspects of: semicondutor material growth and processing; solid-state source performance; device and circuit characterization, de-embedding and modeling; and automated testing. Next, a discussion is provided of the semiconductor device types and circuit media which serve as building blocks for this technology. Device types treated here include sources, mixer/detectors, and modulators. The material offered relating to circuit media contrasts the attributes of monolithic approaches with those of waveguide and hybrid techniques. The paper concludes with a description of salient monolithic programs which benchmark the status of current effort in the U.S. This description includes a summary of important technical issues and research thrust
lhft_intern.bib::Schmidt21

Millimeter-wave monolithic integrated receiver circuits - Schmidt, Lorenz-Peter; Adelsecl, B; Colquhoun, A; Dämbkes, H (AGARD No. 482 Advances on Components for Active and Passive Airborne Sensors, 1990)
lhft_intern.bib::Schmidt18

Millimeter-Wave Radar Image Reconstruction in Heterogeneous Media - Ullmann, Ingrid (47th European Microwave Conference (EuMC), Workshop on Short Range mmWave Imaging Systems, 2017)

Millimeter Wave Radar Imaging for Non-Destructive Detection of Material Defects - Ullmann, Ingrid; Adametz, Julian; Oppelt, Daniel; Vossiek, Martin (18th International Conference on Sensors and Measurement Technology (SENSOR 2017), 2017)

MIMO-FMCW Radar-Based Parking Monitoring Application With a Modified Convolutional Neural Network With Spatial Priors - Martinez Garcia, Javier; Zoeke, Dominik; Vossiek, Martin (IEEE Access, 2018)
Radar imaging is a competitive option for smart city applications over optical approaches, as it raises no privacy concerns. The inherent difficulty of interpreting radar signals can be overcome using deep learning techniques to leverage the capabilities of monitoring sensors with a minimum of human intervention. In this paper, we use a modified convolutional neural network (CNN) for classifying radar images in order to detect vacant parking spaces with a 77-GHz imaging radar. Although training CNNs for radar-image classification is challenging due to poor generalization performance caused by the lack of labeled training data, the modified architecture takes into account the properties of the radar image in order to introduce prior information into the model and improve performance. A MIMO-FMCW radar is utilized to render a slant-range image of a parking scenario, and the image patches corresponding to each parking location are classified independently in the CNN. Since the radiation pattern of a MIMO array varies as a function of the scanning angle, the corresponding spatial coordinate of each patch is included as an additional feature in the upper layers of the network. This allows the model to combine local features from each patch with global scenario information in order to learn robust features that generalize properly to new scenarios. Several models are trained end to end with data from four different parking scenarios and evaluated in a 4-fold cross-validation scheme, and performance is improved when spatial prior information is include
lhft_intern.bib::Martinez18d

MIMO FMCW Reader Concept for Locating Backscatter Transponders - Appel, Sönke; Berges, Dominic; Mueller, Dominikus; Ziroff, Andreas; Vossiek, Martin (IEEE Transactions on Microwave Theory and Techniques, 2016)
This paper presents a multiple-input multiple-output (MIMO) frequency-modulated continuous-wave (FMCW) reader concept for locating backscatter radio-frequency identification (RFID) transponders. The proposed MIMO concept enables transmitter sided digital beamforming after a measurement has been executed. An algorithm is presented to decompose the MIMO response to match a digital beamforming input matrix. A 2.4-GHz experimental reconfigurable localization system based on FMCW technology was set up to demonstrate the concept. Multichannels are implemented to allow the possibility of testing the MIMO concept. A frequency-division multiplexing was implemented into an MIMO FMCW RFID reader and successful tested. Moreover, the system is able to locate multiple transponders simultaneously. Measurements confirm the functionality of the concept. The implementation of a digital beamforming algorithm shows the possibility of transmitting and receiving sided spatial filtering. Angle and distance precision were determined in an antenna chamber as well as in a harsh multipath environment. To help readers to compare the system with others, the mean absolute error of the position shows the system accuracy in a laboratory environment. Finally, an error analysis of the decomposition algorithm verified its robustness.
Keywords: Chirp modulation; frequency-division multiplexing (FDM); multiple-input multiple-output (MIMO); position measurement; radio-frequency identification (RFID) tags; spatial filters; transponders

MIMO Radar-Based Rotation Parameter Estimation of Non-Cooperative Space Debris Objects - Kammel, Christoph; Ullmann, Ingrid; Vossiek, Martin (Proceedings of the IEEE Radar Conference, 2023)
This paper presents an approach to determine the rotation parameters of a non-cooperative space debris object by extracting, localizing and tracking the target's dominant scatterers with a millimeter-wave MIMO radar system. An unscented Kalman filter tracks the scatterer positions over several processing intervals and is therefore able to estimate the rotation period of the target as well as the position and orientation of its rotation axis. On the one hand, the proposed algorithm is validated by realistic simulations. On the other hand, the filter performance under different rotation parameters is evaluated by different measurements in the laboratory.
Created from Fastlane, Scopus look-up
Keywords: autonomous rendezvous; MIMO radar; space debris; unscented Kalman filter

MIMO Radar for Supporting Automated Rendezvous Maneuvers with Non-Cooperative Satellites - Martinez Garcia, Javier; Thurn, Karsten; Vossiek, Martin (IEEE Radar Conference, 2017)

MIMO-SAR Based Millimeter-Wave Imaging for Contactless Assessment of Burned Skin - Oppelt, Daniel; Adametz, Julian; Groh, Jannis; Goertz, Ole; Vossiek, Martin (International Microwave Symposium (IMS2017), 2017)

Miniaturized Regenerative Backscatter Transponder with Bidirectional Communication - Carlowitz, Christian; Vossiek, Martin (43th European Microwave Week / EuRAD, 2013)
For future innovative RFID and radar applications like precisely tracking tools or objects in large environments, miniaturized modulated active backscatter transponders enhanced with bidirectional communication functionality are proposed as a versatile but yet low complexity and low power solution. In this paper, an active backscatter transponder at 5.8 GHz based on a switched injection-locked oscillator as sole RF component is extended by pulse width based received power level detection and enhanced backscatter modulation techniques in order to provide a complete AM transceiver with minimal additional and overall hardware effort. This concept delivers an attractive combination of a high efficiency super-regenerative communication circuit and a powerful regenerative sampling radar transponder in the same RF circuit consisting of a single oscillator. Its implementation (24 × 17 mm) is verified experimentally and shows a high receiver sensitivity that enables communication over the full radar operating range. © 2013 EMA.
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.miniat
Keywords: communication; injection-locked oscillator; radar transponders; radio frequency identification

Mit Bürgerinnen und Bürgern über Forschung und technische Innovationen in der Palliativversorgung ins Gespräch kommen – Pilotierung eines ELSI-Cafés - Öhl, Natalie; Weisser, Alina; Ott, Tabea; Grießhammer, Stefan; Yip, Julia; Klinger, Isabell; Kölpin, Alexander; Miehling, Jörg; Bräuning, J.; Dabrock, Peter; Steigleder, Tobias; Ostgathe, Christoph; et al. (Zeitschrift für Palliativmedizin, 2024)

Mixed-Signal Test Development using Open Standard Modeling and Description Languages - Lu, Ping; Glaser, Daniel; Uygur, Gürkan; Weichselgartner, Susanne; Helmreich, Klaus; Lechner, Armin (Proceedings, 2009)
A novel virtual platform is presented, providing CAD/CAT support for efficient test development and attempting to bridge the gap between design and test. The platform, which models and simulates the entire test environment, provides methodologies, model libraries and tool sets to enable design, debug and verification of all test relevant processes including fault analysis, test algorithm, load board and test program development concurrently with IC design and fabrication phase and later smoothly apply the results to various test systems. One major idea of our work is adopting the open standards approach to guarantee interoperability. In addition, modeling methodologies for virtual tester and virtual silicon are proposed to further enhance interoperability between virtual and real test. To give an insight on how such environment seamlessly integrates into the test development flow, an ADC test which is performed both on the virtual platform and the real tester is described. The simulation environment is built using SystemC/-AMS libraries. © 2009 IEEE.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.c3scha.mixeds

ML Detection without CSI for Constant-Weight Codes in THz Communications with Strong Phase Noise - Wu, Yifei; Koch, Johannes; Vossiek, Martin; Schober, Robert; Gerstacker, Wolfgang (2022 IEEE Global Communications Conference, GLOBECOM 2022 - Proceedings, 2022)
To meet the ever-increasing requirements of high-rate data transmission, the significant amount of spectrum available in the TeraHertz (THz) band is considered for future wireless communications. However, the performance of THz communications is limited by strong phase noise (PN) introduced by oscillators and the complexity added by channel state information (CSI) acquisition. To overcome such impediments, we propose a new transmission concept based on constant-weight (CW) codes which enable low-complexity maximum-likelihood (ML) sequence detection at the receiver side in the presence of strong PN without requiring statistical or instantaneous CSI knowledge. In addition, the error rate of the ML receiver for the proposed CW codes is analyzed. Simulation results verify the analytical derivations and illustrate that the proposed transmission scheme outperforms transmission with on-off keying modulation and coherent detection.
CRIS-Team Scopus Importer:2023-03-07

MMICs for automotive and traffic applications - Coloquhoun, A; Schmidt, Lorenz-Peter (GaAs IC Symp, 1992)
A number of applications of microwave and, in particular, millimeter-wave MMICs (monolithic microwave integrated circuits) in automotive systems are under development. The authors review these applications and give the current status of some of these developments. The applications considered are sensors (both radar and radiometric), communication systems, and traffic control systems. MMICs for the following specific systems are considered: speed sensors, electronic toll collection, and collision avoidance rada
lhft_intern.bib::Schmidt24

MMIC technology in Europe for millimeter-wave applications (invitedpaper) - Dämbkes, H; Schmidt, Lorenz-Peter (GaAs92 - European GaAs Application Symposium, 1992)
lhft_intern.bib::Schmidt27

Mobile robot 6D pose estimation using a wireless localization network - Dobrev, Yassen; Reustle, Christoph; Pavlenko, Tatiana; Cordes, Florian; Vossiek, Martin (2016 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, ICMIM 2016, 2016)
Global navigation satellite systems (GNSS) are widely used for localization on Earth, but are not available on other planets, so that robotic planetary exploration missions need to use alternative methods for localization. This paper presents a wireless localization network (WLN) for estimating the 3D position and 3D orientation of a mobile robot. It consists of at least one reference 24 GHz radar node with known pose, and a mobile node on the robot. The reference nodes can determine the distance and both spatial angles to the mobile robot (thus locating it in 3D) using round-trip time of flight measurements and digital beamforming. We use an extended Kalman filter (EKF) to fuse these results with the readings from the mobile node, and an inclinometer to determine the complete 6D pose of the mobile robot. Measurements in a realistic scenario prove the feasibility of the proposed concept.
Keywords: 6D pose estimation; secondary radar; sensor fusion; wireless localization

Model-based compressed sensing of fiber Bragg grating arrays in the frequency domain - Werzinger, Stefan; Gottinger, Michael; Gussner, Sandra; Bergdolt, Sven; Engelbrecht, Rainer; Schmauß, Bernhard (International Conference on Optical Fiber Sensors (OFS), 2017)
We propose a model-based compressed sensing (MBCS) of FBG arrays (FBGA), interrogated with wavelength scanning incoherent optical frequency domain reflectometry. This method measures the frequency response of a FBGA with an electrical vector network analyzer combined with a tunable laser. Instead of the usual inverse discrete Fourier transform (IDFT), we apply a direct estimation of the grating reflectivities with a simple frequency domain model. A reconstruction of 10 gratings spaced by 20 cm is demonstrated. MBCS allows to reduce the number of measurement frequencies from 120 to 8, compared to an IDFT, while using a bandwidth of just 500 MHz. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use onl
lhft_intern.bib::Werzinger2017b

Model-Based Position and Reflectivity Estimation of Fiber Bragg Grating Sensor Arrays - Werzinger, Stefan; Zibar, Darko; Köppel, Max; Schmauß, Bernhard (Sensors, 2018)
We propose an efficient model-based signal processing approach for optical fiber sensing with fiber Bragg grating (FBG) arrays. A position estimation based on an estimation of distribution algorithm (EDA) and a reflectivity estimation method using a parametric transfer matrix model (TMM) are outlined in detail. The estimation algorithms are evaluated with Monte Carlo simulations and measurement data from an incoherent optical frequency domain reflectometer (iOFDR). The model-based approach outperforms conventional Fourier transform processing, especially near the spatial resolution limit, saving electrical bandwidth and measurement time. The models provide great flexibility and can be easily expanded in complexity to meet different topologies and to include prior knowledge of the sensors. Systematic errors due to crosstalk between gratings caused by multiple reflections and spectral shadowing could be further considered with the TMM to improve the performance of large-scale FBG array sensor systems. View Full-Text</
lhft_intern.bib::Werzinger2018c

Modeling and Design of IRS-Assisted Multi-Link FSO Systems - Ajam, Hedieh; Najafi, Marzieh; Jamali Kooshkghazi, Vahid; Schmauß, Bernhard; Schober, Robert (IEEE Transactions on Communications, 2022)
In this paper, we investigate the modeling and design of intelligent reflecting surface (IRS)-assisted optical communication systems, which can circumvent the line-of-sight (LOS) requirement in multi-link free space optical (FSO) systems. The FSO laser beams incident on the optical IRSs have a Gaussian power intensity profile and a nonlinear phase profile, whereas the plane waves in radio frequency (RF) systems have a uniform power intensity profile and a linear phase profile. Given these substantial differences, the results available for IRS-assisted RF systems are not applicable to IRS-assisted FSO systems. Therefore, we develop a new analytical channel model for point-to-point IRS-assisted FSO systems based on the Huygens-Fresnel principle. Our analytical model captures the impact of the size, position, and orientation of the IRS as well as its phase shift profile on the end-to-end channel. To allow the sharing of the optical IRS by multiple FSO links, we propose three different protocols, namely the time division (TD), IRS-division (IRSD), and IRS homogenization (IRSH) protocols. The proposed protocols address the specific characteristics of FSO systems including the non-uniformity and possible misalignment of the laser beams. Furthermore, to compare the proposed IRS sharing protocols, we analyze the bit error rate (BER) and the outage probability of IRS-assisted multi-link FSO systems in the presence of inter-link interference. Our simulation results validate the accuracy of the proposed analytical channel model for IRS-assisted FSO systems and confirm that this model is applicable for both large and intermediate IRS-receiver lens distances. Furthermore, we show that for the proposed IRSD and IRSH protocols, inter-link interference becomes negligible if the laser beams are properly centered on the IRS and the transceivers are carefully positioned, respectively. Moreover, in the absence of misalignment errors, the IRSD protocol outperforms the other protocols, whereas in the presence of misalignment errors, the IRSH protocol performs significantly better than the IRSD protocol.
CRIS-Team Scopus Importer:2022-04-15
Keywords: Analytical models

Modeling Conductor Surface Roughness - Gold, Gerald; Helmreich, Klaus (IMS 2017 Workshop on New Developments in Microwave Measurements for Planar Circuits and Components, 2017)

Modeling of microwave-excited gas discharges - März, Martin (Archiv fuer Elektrotechnik, 1994)
This paper is dealing with the power density versus electric field characteristic of microwave-excited discharges on the example of typical CO2 laser gas discharges. The fundamentals of the method are a simple electric equivalent circuit for the excitation structure and the assumption of a fixed reduced electric field intensity within the plasma. This operating field is enforced by the plasma under stationary conditions and can be calculated using an electron balance under consideration of the non-Maxwellian electron energy distribution function. The calculations turn out that c.w. excitation with microwaves is involved with considerable plasma power densities. In the case of the CO2 laser this requires special discharge channel designs for effective gas cooling. Besides a discussion of the plasma characteristic, measurements taken from a microwave applicator are presented and compared to the calculations. © 1994 Springer-Verlag.
Created from Fastlane, Scopus look-up

Modeling of Transmission Lines with Multiple Coated Conductors - Gold, Gerald; Helmreich, Klaus (46th European Microwave Week, 2016)
lhft_intern.bib::Gold2016a

Modeling Surface Roughness in CST Microwave Studio - Gold, Gerald (Computer Simulation Technology - European User Conference (EUC), 2016)
lhft_intern.bib::Gold2016b

Modellierung rauher Oberflächen und Materialcharakterisierung für den Entwurf von Leiterplatten für Hochfrequenzanwendungen - Gold, Gerald (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)
UnivIS-Import:2016-07-26:Pub.2016.tech.IE.c3scha.modell

Modellierungsansätze und Signalverarbeitung für ein mit niederfrequenten Magnetfeldern arbeitendes inkohärentes lokales Ortungssystem - Hehn, Markus (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2021)
Auf magnetischen Wechselfeldern basierte Ortungssysteme sind ein vielversprechender Kandidat als Ortungssystem für den lokalen Bereich, da sie im Gegensatz zu wellenbasierten Ortungssystemen nicht von Mehrwegeausbreitung, Schwund oder Abschattung durch nichtmetallische Materialien wie Möbel, Wände oder Menschengruppen beeinflusst werden. Da die verwendeten Modelle und Algorithmen maßgeblich zur Leistungsfähigkeit beitragen, befasst sich diese Arbeit mit der Modellierung und Signalverarbeitung von auf magnetischen Wechselfeldern basierten Ortungssystemen. Zur Vermeidung aufwendiger Hardware und Verfahren zur Synchronisierung ist es wünschenswert, alle Komponenten des Ortungssystems inkohärent zu betreiben. Daher wird in dieser Arbeit ein magnetisches Ortungssystem vorgestellt, welches die Position und Orientierung eines einachsigen magnetischen Senders anhand der Messwerte von mehreren im Raum verteilten, inkohärenten, dreiachsigen Feldsensoren schätzen kann. Im ersten Teil dieser Arbeit werden das Modell und die Simulationsergebnisse von kreisförmigen Spulen gezeigt sowie mithilfe der elektromagnetischen Feldtheorie unterschiedliche Modelle des durch den magnetischen Sender im Freiraum generierten Magnetfelds und von einachsigen Sensorspulen beschrieben. Die beschriebenen Modelle des Senders und des Sensors können beliebig kombiniert und für beliebige Komponentenorientierungen eingesetzt werden. Außerdem werden netzwerktheoretische Modelle der magnetischen Verkopplung zwischen Sende- und Sensorspule sowie von möglichen Architekturen des magnetischen Senders hergeleitet. Anhand der Modelle wird gezeigt, wie die Spulen für eine große Systemreichweite dimensioniert werden müssen. Zur kompakten Erfassung der drei Freiheitsgrade des Magnetfelds werden in dieser Arbeit dreiachsige Feldsensoren verwendet, welche nichtideale Effekte, wie eine magnetische Verkopplung der Spulen, eine Fehlorientierung der Spulen oder eine Verdrehung des Feldsensors gegenüber des globalen Koordinatensystems, aufweisen können. Diese Effekte werden mathematisch modelliert und es wird gezeigt, dass sie sich zu einer invertierbaren Matrix zusammenfassen lassen. Bei der mathematischen Modellierung des magnetischen Ortungssystems wird gezeigt, dass die Orientierungsbeschreibung des Senders mit einer Drehmatrix, die ein Element einer Lie-Gruppe ist, vorteilhaft ist und somit ein Systemzustand einer zusammengesetzten Lie-Gruppe geschätzt werden muss. Es werden Bedingungen zur eindeutigen Schätzbarkeit des Systemzustands hergeleitet und gezeigt, unter welchen Randbedingungen das Ortungsproblem prinzipiell lösbar ist. Da die Feldsensoren inkohärent betrieben werden, wird in dieser Arbeit das magnetische Ortungssystem als inkohärentes Messsystem beschrieben. Auf Basis der Modelle wird ein Kalibrierverfahren gezeigt, um die störenden, nichtidea- len Effekte der Feldsensoren kompensieren zu können. Außerdem wird ein Kalman-Filter-Algorithmus beschrieben, welcher mit komplexwertigen Messungen eines inkohärenten Messsystems und eines Systemmodells einen Lie-Gruppen-Systemzustand schätzen kann. Zusätzlich wird die Schätzung eines LieGruppen-Systemzustands mit alleiniger Auswertung von komplexwertigen Messungen eines inkohärenten Messsystems als Maximum-Likelihood-Problem formuliert und Lösungen hierfür vorgestellt. Da die Orientierung des magnetischen Senders aufgrund der Rotationssymmetrie der Spule nur zwei Freiheitsgrade aufweist, wird gezeigt, wie die Algorithmen zur stabilen Schätzung eines Lie-Gruppen-Systemzustands mit einer verringerten Anzahl an Freiheitsgraden angepasst werden müssen. Die in dieser Arbeit vorgestellten Modelle und Algorithmen wurden mithilfe von Simulationen und anhand eines Messaufbaus evaluiert. Im Messaufbau wurde durch vorherige Kalibrierung und der in dieser Arbeit gezeigten Algorithmen eine Positionsgenauigkeit von 3,8 cm bis 4,9 cm und eine Orientierungsge- nauigkeit von 3,5◦ bis 4,5◦ er

Modellierung und Simulation eines OTDM Empfängers - Hofmann, Arnd; Schmauß, Bernhard (Workshop der ITG Fachgruppe 5.3.1., 2001)
UnivIS-Import:2015-04-16:Pub.2001.tech.IE.LEH.modell

Modelling and Construction of Complex Shaped Polyvinyl Alcohol based Ultrasound Phantoms for Inverse Magnetomotive Ultrasound Imaging - Heim, Christian; Huber, Christian; Ermert, Helmut; Ullmann, Ingrid; Saleem, Taimur; Lyer, Stefan; Rupitsch, Stefan Johann (22. GMA/ITG-Fachtagung Sensoren und Messsysteme 2024, 2024)
With regard to the application in local cancer treatment, the inverse magnetomotive ultrasound (IMMUS) modality needs to be extended to 3D on complex shaped polyvinyl alcohol (PVA) phantoms. Our four basic construction elements can be combined step-by-step to manufacture such complex shaped phantoms. The construction of complex shaped ultrasound phantoms requires the four basic elements (i) molds, (ii) scattering material, (iii) layering process, and (iv) mechanical coupling between different parts of the phantom. In this contribution, we describe the construction elements in detail to show the trade-offs between the possible shapes and positioning of the encapsulated volumes and the production time. Furthermore, since IMMUS requires knowledge of the mechanical parameters and the geometry of the target tumorous tissue, these parameters have to be determined during a magnetic drug targeting (MDT) therapy. The insertion of MDT therapy relevant amount of superparamagnetic iron oxide nanoparticles (SPIONs) does not significantly change the material properties. Therefore, quantitative ultrasound-based tissue characterization techniques (UTCT) such as shear wave elastography (SWE) or transient elastography (TE) can be used to characterize the target tumorous tissue once in advance of an MDT therapy. In this contribution, SWE and TE are exploited to determine shear wave velocity in PVA phantoms. Both methods show promising results for the determination of Young's modulu
Keywords: Magnetic Drug Targeting; Magnetic Nanoparticles; Magnetomotive Ultrasound Imaging; Polyvinyl Alcohol Ultrasound Phantom; Ultrasound-based Material Characterization

Modelling and performance study of monolithically integrated depletion type Silicon IQ modulators - Mehrpoor, Gilda Raoof; Wohlfeil, Benjamin; Eiselt, Michael; Zimmermann, Lars; Rito, Pedro; Eibers, Jörg Peter; Schmauß, Bernhard (Photonische Netze - 19. ITG-Fachtagung, 2020)
We report on an analytical model for monitoring the bias condition of Silicon IQ modulators. Based on measured phase modulator behavior, ohmic heaters and modulator transfer functions, transmitter performance investigation is attained versus applied bias voltages. We underline error vector magnitude and quadrature error as appropriate metrics for quality measurements of Silicon coherent transmitters.
CRIS-Team Scopus Importer:2021-04-19

Modified ladder-type 2.4GHz SAW filter with transmission zero - Novgorodov, Volodymyr; Freisleben, Stefan; Heide, Patric; Vossiek, Martin (IEEE International Ultrasonics Symposium 2010, 2010)
lhft_intern.bib::Novgorodov2010

Modular Hardware Design for High-Performance MIMO-Capable SDR Systems to Accelerate 6G Development - Karle, Christian; Neu, Marc; Nuss, Benjamin; Chen, Jiayi; Witte, Lukas; Scheder, André; Harbaum, Tanja; Becker, Jurgen (2024 IEEE 37th International System-on-Chip Conference (SOCC), 2024)
Compared to 5th generation (5G), 6G is expected to offer latencies below 1 ms, higher data rates in the range of multiple Gbit/s, and enable the use of new frequency bands and application fields such as joint-communication and sensing (JCAS). For the development of the new mobile standard, research, and industry are increasingly relying on the use of high-performance multiple-input multiple-output (MIMO)-capable software-defined radio (SDR) systems. However, existing systems are often limited in their applicability due to bandwidth, frequency, and performance limitations by manufacturer-specific hardware. To overcome these limitations, we present a modular hardware design for a high-performance MIMO-capable SDR system. We enable the exchange of the digital processing unit, the replacement, or configuration of the analog IF front ends, and the configurability of the clock distribution network. Therefore, our system achieves high adaptability compared to manufacture-specific systems. To match the changing requirements in 6G, our modular SDR system bypasses the time-consuming and costly hardware design process and accelerates the overall development. Finally, we demonstrate the performance of our modular SDR system by implementing a high-performance orthogonal frequency-division multiplexing (OFDM) radar, which requires high sampling and data rates processed in real-time. Based on our high-performance example application, our modular SDR system matches the performance of fixed-structure SDR systems, required for 6G.
CRIS-Team Scopus Importer:2024-12-13
Keywords: 6G; modular hardware design; RFSoC; SDR system

Moeglichkeiten, Grenzen und Anwendungsbeispiele der drahtlosen und energieautarken Sensorik - Vossiek, Martin; Kirsch, Fabian (Mikrosysteme und Energie - von der Planung bis zur Fertigung, 2012)
lhft_intern.bib::Vossiek2012zempro

Moeglichkeiten und Grenzen zur FMCW-Radar basierten Ortung von Backscatter RFID-Tags in Umgebungen mit stark gestoerten Mehrwege-Kanälen - Ebelt, Randolf; Li, Gang; Vossiek, Martin (RADCOM 2011 - Workshop, Developer Forum and Exhibition, 2011)
lhft_intern.bib::Ebelt2011b

Möglichkeiten und Grenzen einer technischen Nutzung der Sonnenenergie - Brand, Hans (VS Verlag für Sozialwissenschaften, 1977)
In den letzten beiden Jahrzehnten hatte sich in dem öffentlichen Bewußtsein unserer Industrienationen bekanntermaßen eine Konsummentalität entwickelt, die weitgehend durch eine unreflektierte Sorglosigkeit gegenüber unseren natürlichen Ressourcen gekennzeichnet war. Erst die Liefereinschränkungen und nachfolgenden Kostensteigerungen bei flüssigen fossilen Brennstoffen um die Jahreswende 1973/74 haben hier eine Wende bewirkt und auch bei einer breiteren Öffentlichkeit das Interesse für die Probleme einer gesicherten Energieversorgung der Zukunft geweckt. In der Fachwelt allerdings wurden langfristige Prognosen des Energiebedarfs und die Möglichkeiten einer Angebotsrealisierung an Energie schon seit vielen Jahren diskutier
lhft_intern.bib::thirty_years_LHFT_38

Moisture detection of materials in leaky cavities using microwave techniques - Penirschke, Andreas; Schüßler, Martin; Vossiek, Martin; Gulden, Peter; Jakoby, Rolf (35th European Microwave Conference, EuMC, 2005)
In order to characterize the moisture of material samples in a leaky, rotating cavity without influencing the process, use was made of microwave techniques to determine the amount of water within the cavity. Moisture measurements where done before and during rotation of the cavity. The extraction of the humidity has been carried out using a Mode Tracking algorithm as well as a classification algorithm based on a Maximum Likelihood approach.
UnivIS-Import:2015-04-16:Pub.2005.tech.IE.LEH.moistu

Monolithic Additively Manufactured Conformal 4x4 MIMO Radar Frontend based on Slotted Waveguide Array Antennas for 77 GHz Corner Radar - Lomakin, Konstantin; Alhasson, Saif; Hofmann, Andreas; Sippel, Mark; Gold, Gerald (2023 IEEE Conference on Antenna Measurements and Applications (CAMA), 2023)
In this work, an additively manufactured MIMO radar antenna setup is presented based on stereolithography 3D-printing of photopolymer resin and subsequent electroplating. The 8 antennas are based on slotted waveguide array design, each with 20 radiating elements along the elevation plane and are combined with an additional horn aperture on top of the radiating elements. The array incorporates two types of antennas which differ within the horn aperture yielding one type with wide azimuthal field of view and the other with a narrow field of view.Moreover, the antenna elements are conformally placed on a bent surface, consequently, directing the maximum gain into different directions.The entire array is manufactured as one monolithic part without the need of tedious assembly steps and thus, enhancing the feasibility towards serial productio

Monolithically Integrated Balanced Photodetector and its Application in ODTM 160 Gbits/s DPSK Transmission - Schmauß, Bernhard; Beling, A.; Bach, H.G.; Schmidt, D.; Mekonnen, G. G.; Ludwig, R.; Ferber, S.; Schubert, C.; Börner, C.; Berger, J.; Schmidt, C.; Troppenz, U.; et al. (Fraunhofer Institute for Telecommunications , Heinrich-Hertz-Institut, Berlin, Juni, 2003)
UnivIS-Import:2015-04-16:Pub.2003.tech.IE.LEH.monoli

MOS-16: A New Method for In-Fixture Calibration and Fixture Characterization - Schramm, Marcus; Schür, Jan; Hrobak, Michael; Schmidt, Lorenz-Peter; Konrad, Michael (ARFTG, 2011)
lhft_intern.bib::Schramm11

Motion Parameter Estimation of Free-Floating Space Debris Objects Based on MIMO Radar - Kammel, Christoph; Ullmann, Ingrid; Vossiek, Martin (IEEE Transactions on Radar Systems, 2023)
This paper presents a novel approach for estimating the motion parameters of noncooperative, free-floating space debris objects by assessing data from a multiple-input multiple-output radar system. The deployment of radar data renders the presented method particularly robust and reliable for use in the challenging space environment, with its frequently encountered harsh lighting conditions. The proposed algorithm initially extracts, locates, and tracks the dominant scatterers of the target by evaluating the range-Doppler diagrams derived from the radar data. Considering both the tracking results and a motion model, a cubature Kalman filter subsequently determines the rotational and translational motion parameters of the debris object, employing dual quaternions to describe its attitude and position. Thereby, the suggested method does not require prior information about the target object, such as its computer-aided design model, thus forming the basis for fully autonomous docking maneuvers and space debris removal. The algorithm was validated in a simulated space scenario and its performance simulatively assessed for small targets in the lower range of analyzability. Using an automated gimbal setup that realizes arbitrary controlled rotational movements, the proposed method was also practically tested in terms of achieved estimation errors and required convergence time. Finally, a comparison with a state-of-the-art unscented Kalman filter was performed to analyze the suitability of the chosen cubature Kalman filter approach.<br
Keywords: Quaternions; Radar; Spaceborne radar; Radar tracking; Target tracking; Space debris; Parameter estimation

Multi-Antenna Data Collector for Smart Metering Networks with Integrated Source Separation by Spatial Filtering - Quednau, Philipp; Trommer, Ralph; Schmidt, Lorenz-Peter (Frequenz, 2016)
Wireless transmission systems in smart metering networks share the advantage of lower installation costs due to the expandability of separate infrastructure but suffer from transmission problems. In this paper the issue of interference of wireless transmitted smart meter data with third party systems and data from other meters is investigated and an approach for solving the problem is presented. A multi-channel wireless m-bus receiver was developed to separate the desired data from unwanted interferers by spatial filtering. The according algorithms are presented and the influence of different antenna types on the spatial filtering is investigated. The performance of the spatial filtering is evaluated by extensive measurements in a realistic surrounding with several hundreds of active wireless m-bus transponders. These measurements correspond to the future environment for data-collectors as they took place in rural and urban areas with smart gas meters equipped with wireless m-bus transponders installed in almost all surrounding buildings.
lhft_intern.bib::Quednau2016

Multi-Channel Distance Measurement with IEEE 802.15.4 (ZigBee) Devices - Pichler, Markus; Schwarzer, Stefan; Stelzer, Andreas; Vossiek, Martin (IEEE Journal of Selected Topics in Signal Processing, 2009)
The addition of positioning capabilities to low-cost communications such as IEEE 802.15.4 compliant (ZigBee) networks can open up interesting markets, in particular if existing hardware and standard communications packets can be used for this purpose. High-precision localization requires large transmission bandwidths and thus the use of multiple frequency-channels. In the presence of oscillator frequency uncertainty the coherent synthesis of individual measurements poses a challenge. This paper proposes a particular frequency-hopping and signal processing scheme by which most transmitter and receiver frequency-errors can be eliminated in signal processing. Measurements show that high precision distance estimation with errors down to a few cm can be achieved. © 2010 IEEE.
UnivIS-Import:2015-03-09:Pub.2009.tech.IE.LEH.multic
Keywords: Frequency hopping; Local positioning; Sensor networks; ZigBee

Multi-channel real-time condition monitoring system based on wideband vibration analysis of motor shafts using SAW RFID tags coupled with sensors - Caldero Bardaji, Pau; Zoeke, Dominik (Sensors, 2019)
While there is a wide range of approaches to monitor industrial machinery through their static components, rotating components are usually harder to monitor, since sensors are difficult to be mounted on them and continuously read during operation. However, the characteristics of rotating components may provide useful information about the machine condition to be included in monitoring algorithms, specially for long-term data analysis. In this work, wireless vibration monitoring of rotating machine parts is investigated using surface acoustic wave (SAW) radio frequency identification (RFID) tags coupled with sensors. The proposed augmented transponder solution, combined with low-latency interrogation and signal processing, enables real-time identification and wideband vibration sensing. On top of that, a multi-channel interrogation approach is used to compensate motion effects. This approach enhances the signal-to-noise ratio of low-power high-frequency components present on the vibration signatures and enables discriminant information extraction from rotating machine parts. Final feasibility is evaluated with induction motors and vibration measurements on rotating shafts are verified. In addition, a condition classification algorithm is implemented in an experimental setup based on different motor states. The results of this work open the possibility to feed predictive maintenance algorithms using new features extracted in real-time from wideband vibration measurements on rotating components.
CRIS-Team Scopus Importer:2019-12-20
Keywords: Augmented RFID; Condition monitoring; IIOT; SAW

Multifunctional and compact 3D FMCW MIMO radar system with rectangular array for medium-range applications - Multerer, Thomas; Miralles, Enric; Ganis, Alexander; Schoenlinner, Bernhard; Prechtel, Ulrich; Meusling, Askold; Mietzner, Jan; Weckerle, Christian; Esteban, Hector; Vossiek, Martin; Loghik, Mirko; Ziegler, Volker (IEEE Aerospace and Electronic Systems Magazine, 2018)
Ever since the era of autonomous systems started, multisensor platforms have become a key topic in aerospace, automotive, and robotics industries. Multifunctional systems integrate more than one sensor and/or actuator in one device and are capable of creating synergies between them. As a consequence, their performance is superior compared to single-sensor systems, for different reasons [1]-[3
lhft_intern.bib::Miralles2018a

Multifunktionales Sensorsystem fuer Prozessueberwachung in Faserverbundwerkstoffen - Javdanitehran, M; Groh, Jannis (Workshop Mikroproduktion von Materialhybriden, 2015)
lhft_intern.bib::Groh2015

Multilevel amplitude and phase regeneration in a nonlinear amplifying loop mirror with a phase-sensitive amplifier - Röthlingshöfer, Tobias; Onishchukov, Georgy; Schmauß, Bernhard; Leuchs, Gerd (Transparent Optical Networks (ICTON), 2012)
A novel regenerator scheme for all-optical multilevel simultaneous amplitude and phase noise suppression is proposed. For a star-8QAM signal, consisting of two amplitude and four phase states, EVM reduction is 4 dB and 2.5 dB for the high- and low-power states, respectively. The limiting effects of the regenerator performance have been considered.
lhft_intern.bib::Roethlingshoefer2012cb

Multilevel Phase-Preserving Amplitude Regeneration Using a Single Nonlinear Amplifying Loop Mirror - Hierold, Martin; Roethlingshoefer, Tobias; Sponsel, Klaus; Onishchukov, Georgy; Schmauß, Bernhard; Leuchs, Gerd (IEEE Photonics Technology Letters, 2011)
lhft_intern.bib::Hierold2011

Multi-modal sensor fusion for indoor mobile robot pose estimation - Dobrev, Yassen; Flores, Sergio Alberto; Vossiek, Martin (IEEE/ION Position, Location and Navigation Symposium, PLANS 2016, 2016)
While global navigation satellite systems (GNSS) are the state of the art for localization, in general they are unable to operate inside buildings, and there is currently no well-established solution for indoor localization. In this paper we propose a 3D mobile robot pose (2D position and 1D orientation) estimation system for indoor applications. The system is based on the cooperative sensor fusion of radar, ultrasonic and odometry data using an extended Kalman filter (EKF). A prerequisite for the EKF is an occupancy grid map of the scenario as well as the pose of the reference radar node inside the map. Our system can handle even the kidnapped-robot case as the radar provides absolute localization. We conducted a series of measurements in an office building corridor. We determined the typical position root-mean square error (RMSE) to be less than 15 cm.
Keywords: indoor localization; mobile robot localization; multi-modal sensor fusion; positioning radar; ultrasonic sensor

Multi-mode dual polarization 94 GHz monopulse antenna - Huder, B; Schmidt, Lorenz-Peter (AGARD No. 482 Advances on Components for Active and Passive Airborne Sensors, 1990)
lhft_intern.bib::Schmidt19

Multipath Sensor Based on GNSS for Passive Airborne Surveillance - Wachtl, Stefan; Koch, V.; Schmidt, Lorenz-Peter (43th European Microwave Week, 2013)
Passive radar systems are of great interest for several kinds of applications and therefore subject of actual research and development. One main application for passive radar systems is airborne surveillance, which includes the detection and tracking of airborne targets. Several passive radar systems based on terrestrial illumination have been demonstrated in the past. In passive radar applications based on satellite systems, a Global Navigation Satellite System (GNSS) can represent the radar transmitter, which illuminates the target, completed by a modified GNSS receiver, which analyses the radar signals. The advantages of this system would be the worldwide availability, the high number of transmitters and the coherent and well known signal structure. The main challenge in this system would be the extremely low signal power received on earth surface. In this paper, a multipath sensor for passive radar applications, which uses the Global Positioning System (GPS) L1 frequency as target illuminator, is demonstrated. Considerations about the expected signal power of multipath signals caused by a target are presented and confirmed through measurements. The main goal of this work is detecting, ranging and tracking a target in speed and distance over time. © 2013 EMA.
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.multip

Multiport Network Analysis at High Frequencies - Ziegler, Christof; Martius, Siegfried; Schmauß, Bernhard; Schmidt, Lorenz-Peter; Hocke, Ralf; Wohlgemuth, O. (6th IEEE Workshop , Signal Propagation on Interconnects, 2002)
This paper describes the problem of characterizing multiport networks at high frequencies, especially such devices which are stimulated by a common-mode or differential-mode source. An overview over the definition of mixed-mode S-parameters and their relation to nodal S-parameters is given. A measurement system is presented, which enables to measure all S-parameters of a 4-port with a 2-port network analyzer in an automated procedure. The functionality of this measurement system is described and possible ways for calibration are shown. ©2002 IEEE.
UnivIS-Import:2015-04-16:Pub.2002.tech.IE.LEH.multip

Multipurpose Polymer Bragg Grating-Based Optomechanical Sensor Pad - Hessler, Steffen; Bott, Patrick; Kefer, Stefan; Schmauß, Bernhard; Hellmann, Ralf (Sensors, 2019)
Flexible epoxy waveguide Bragg gratings are fabricated on a low-modulus TPX™ polymethylpentene polyolefin substrate for an easy to manufacture and low-cost optomechanical sensor pad providing exceedingly multipurpose application potentials. Rectangular EpoCore negative resist strip waveguides are formed employing standard UV mask lithography. Highly persistent Bragg gratings are inscribed directly into the channel waveguides by permanently modifying the local refractive indices through a well-defined KrF excimer laser irradiated +1/-1 order phase mask. The reproducible and vastly versatile sensing capabilities of this easy-to-apply optomechanical sensor pad are demonstrated in the form of an optical pickup for acoustic instruments, a broadband optical accelerometer, and a biomedical vital sign sensor monitoring both respiration and pulse at the same time.
CRIS-Team Scopus Importer:2019-10-01
Keywords: accelerometer; Bragg grating; EpoCore; guitar pickup; TPX; vital sign sensor

Multirate Universal Radar Target Simulator for an Accurate Moving Target Simulation - Körner, Georg; Hoffmann, Marcel; Neidhardt, Steffen; Beer, Matthias; Carlowitz, Christian; Vossiek, Martin (IEEE Transactions on Microwave Theory and Techniques, 2021)
This article presents a new universal radar target simulator (RTS) principle based on multirate sampling. The proposed concept enables a realistic emulation of moving targets independently of the radar type and signal and is suited for all common modulation types, such as frequency-modulated continuous-wave (FMCW), chirp sequence (CS), orthogonal frequency division multiplexing (OFDM), and pseudorandom impulse sequences. This versatile applicability is achieved by delaying the radar signal with a time-variant delay that is changed continuously over time. Analog systems use mixing to simulate moving targets, which is not precise. Standard digital radio frequency memory (DRFM) systems with discrete programmable time delays, in contrast, typically drop or delay samples to simulate moving targets. This time-delay discretization, however, introduces discontinuities to waveforms and therefore creates spurious signals. These distortions particularly affect processing in the Doppler dimension. To overcome this disadvantage, the proposed multirate system simulates continuous target movement and the Doppler effect of real targets by using different sample rates for an analog-to-digital converter (ADC) and digital-to-analog converter (DAC). The resulting Doppler phase variation equals that of a real moving target exactly. With this multirate RTS, even slow-moving real-world targets can be mimicked accurately. The attractive properties of the proposed RTS concept are verified by real-world measurements with a 77-GHz demonstration syste

Multisensor Based Indoor Vehicle Localization System for Production and Logistic - Fuentes, Michel Juan Carlos; Christmann, Mark; Fiegert, Michael; Gulden, Peter; Vossiek, Martin (IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems, 2006)
In this paper a multisensor based indoor vehicle localization system for production and logistics is introduced. To track the position and the orientation of a moving vehicle a set of distance values to several points on the vehicle is measured by a wireless ranging system. The beacons of the wireless system are mounted at known positions in the surrounding infrastructure. It is shown that conventional multilateralization is not very practical to solve the required positioning task. In order to match the complete geometry of the forklift to a set of measured distance data, a heuristic nonlinear optimization method is applied. With our novel approach it is possible to solve the complex underlying transformation problem and to calculate the position and angle of the forklift for nearly arbitrary measuring conditions. The achieved accuracy is optimal in the least squares sense. For situations where the wireless access to the vehicle is disturbed, the localization system is assisted by data from a laser scanner. By matching subsequent scans relative movements of the vehicle are be determined precisely. The fusion of an optical relative sensors and a wireless absolute localization system allows for a flexible and steady control of transportation processes even in complex and dynamically changing environments. © 2006 IEEE.
UnivIS-Import:2015-04-16:Pub.2006.tech.IE.LEH.multis

Multi-span digital non-linear compensation for dual-polarization quadrature phase shift keying long-haul communication system - Schmauß, Bernhard; Holtmannspötter, Michael; Lin, Chien-Yu; Asif, Rameez (Optics Communications, 2012)
We have numerically investigated a method to reduce the complexity of the digital backward propagation algorithm (DBP). A filtered logarithmic step-size based split-step Fourier method (SSFM) is investigated in this paper to digitally compensate chromatic dispersion (CD) and non-linearities (NL) in dual-polarization quadrature phase shift keying (DP-QPSK) systems. The algorithm was evaluated for coherently-detected multiple channel DP-QPSK system over un-compensated transmission links with diverse baud-rates i.e. 14 GBaud, 28 GBaud and 56 GBaud. The results depict efficient mitigation of CD and NL, therefore improving the non-linear threshold point (NLT) by 4 dB. Furthermore by implementing a low-pass-filter (LPF) in each DBP stage, the required number of DBP stages are significantly reduced (multi-span DBP) by 75%. The results delineate improved system performance of logarithmic step size based filtered DBP (FL-DBP) both in terms of efficiency and complexity which will be helpful in future deployment of DBP algorithm with real-time signal processing modules for non-linear compensation. © 2011 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2012.tech.IE.LEH.multis
Keywords: Coherent receiver; Digital backward propagation; Dispersion; Non-linearities; Optical fiber communication; Phase modulation

Multistatic GNSS Receiver Array for Passive Air Surveillance - Wachtl, Stefan; Koch, Volker; Westphal, Robert; Schmidt, Lorenz-Peter (Frequenz, 2016)
The performance of a passive air surveillance sensor based on Global Navigation Satellite Systems (GNSS) is mainly limited by the receiver noise efficiency, the achievable signal processing gain and the radar cross section (RCS) of an airplane. For surveillance applications large detection ranges as well as a high probability of detection are crucial parameters. Due to the very low GNSS signal powers received on the earth’s surface, high radar cross sections are mandatory to achieve detection ranges for airplanes at some kilometers distance. This paper will discuss a multistatic transmitter and receiver arrangement, which is indispensable to get a reasonable detection rate with respect to a hemispheric field of view. The strong performance dependency of such a sensor on the number of transmitters and receivers will be shown by means of some exemplary simulation result
lhft_intern.bib::Wachtl2016

Multistatic/MIMO Close-Range Imaging Radar: Realization and Challenges - Ahmed, S.; Adametz, Julian; Gumbmann, Frank; Schiessl, Andreas; Schmidt, Lorenz-Peter; Vossiek, Martin (IEEE IMS 2014 Workshop on MIMO Radar Techniques and Frontends for Localization and Imaging, 2014)
lhft_intern.bib::Ahmed2014

Multistatic/MIMO Close-Range Imaging Radar: Theory and Concepts - Adametz, Julian; Ahmed, S.; Gumbmann, Frank; Schiessl, Andreas; Schmidt, Lorenz-Peter; Vossiek, Martin (IEEE IMS 2014 Workshop on MIMO Radar Techniques and Frontends for Localization and Imaging, 2014)
lhft_intern.bib::Adametz2014

Multistatic mm-Wave Imaging with Planar 2D-Arrays - Ahmed, S. S.; Schießl, Andreas; Schmidt, Lorenz-Peter (GeMiC 2009, 16 - 18 March, München, Germany, 2009)
This work reports measurement results for the scanning of 2D and 3D objects in W-band (75 to 110 GHz) using active 2D planar arrays in multistatic configuration with digital beamforming technique. The image quality of the object reflectivity depends mainly on the frequency band, array configuration, signal polarization, and focusing method. Multistatic measurements allow for higher dynamic range, reduced antennas count and the feasibility for cross-polarization measurements. Measurements meet the theoretical expectation and the simulation results down to 4 mm resolution. Two multistatic arrays will be presented and compared in terms of image resolution, antennas count, SNR and digital processing needed.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.LEH.multis
Keywords: Back-propagation; Digital beamforming; Imaging; Mm-wave; Point spread function; Signal to noise ratio

Multistatic Short Range Ka-Band Imaging System - Gumbmann, Frank; Tran, Hue Phat; Weinzierl, Jochen; Schmidt, Lorenz-Peter (GeMIC 2009, München, March, 2009)
This paper presents the concept of a Ka-Band (26.5 - 40 GHz) multistatic active short range imaging system. The motivation for this work was the development of a fast scanning imaging system for non destructive testing (NDT) or securityscenarios. The goal was to derive a 3D reconstruction of thedevice under test (DUT). The imaging system consists of a linear receive array and spatially distributed transmitters with non focussing antenna elements. This transmit/receive array receiveris moved perpendicular to the array dimension. By switching device between each transmitter and simultaneous reception of the IDUT)scattered field by each receiver, a fast sampling of the 2D aperture plane is achieved. Due to unfocussed antenna elements Ynumerical reconstruction algorithms have to be applied for a lateral resolution. An aperture synthesis concept is presented R to reconstruct the raw data. It is based on the separation 7R-7of the reconstruction kernel into a horizontal and a vertical part. Range resolution is achieved by a broadband stepped frequency continuous wave.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.LEH.multis_1

Multi-Static Synthetic Aperture Radar for Earth Monitoring: Challenges, Innovative Solutions, and Demonstrations Using Swarms of Drones - Villano, Michelangelo; Peixoto, Maxwell Nogueira; Kim, Sumin; Mustieles Perez, Victor; Ustalli, Nertjana; Scala, Francesca; Börner, Thomas; Mittermayer, Josef; Krieger, Gerhard; Moreira, Alberto (APSAR 2023 - 2023 8th Asia-Pacific Conference on Synthetic Aperture Radar, 2023)
Spaceborne synthetic aperture radar (SAR) is an essential tool for Earth observation applications. By combining multiple SAR images taken from different viewing angles, precise digital elevation models and high-resolution tomograms can be created, revealing the three-dimensional structure of vegetation, ice, and dry soil. Currently, such images are typically acquired sequentially, impacting product quality and limiting our ability to monitor rapid changes effectively. Multi-static SAR systems bring new possibilities by enabling the simultaneous collection of all necessary data, promising more effective and robust planetary monitoring. However, a significant challenge lies in developing multi-static concepts capable of generating high-quality digital elevation models and tomograms from sets of noisy and undersampled radar data acquired by clusters of smallsats with compact antenna apertures. To address this, swarms of drones equipped with radars and localization systems offer an affordable option for testing multi-static concepts and acquiring data with sub-hour temporal resolution.
CRIS-Team Scopus Importer:2024-12-16
Keywords: digital elevation models (DEMs); drones; interferometry; multi-static concepts; satellite swarms; synthetic aperture radar (SAR); tomography

Nahfeldlokalisierung von Systemen in Produktionslinien - Gulden, Peter; Fischer, Christian; Lipka, Melanie; Marschall, Albert; Fritzsch, Thomas; Franke, Jörg; Vossiek, Martin (MikroSystemTechnik Kongress 2015 "MEMS, Mikroelektronik, Systeme", Proceedings, 2015)
The continuous tracking of tool positions and transport means is an important factor in terms of efficiency and tracking of safety relevant production steps. The research project NaLoSysPro investigates a novel solution for tracking the assembly tools for screws and nuts at a manual work station. The project targets miniaturization steps like 24 GHz RF chip-design and antenna module integration as well as novel positioning algorithms and individual worker guidance during assembly. A setup consisting of worker information system, work station and wireless positioning system will be realized during the project.
lhft_intern.bib::Lipka15a

Nahfeldlokalisierung von Systemen in Produktionslinien – Hardware und Systemintegration - Fritzsch, T; Gulden, P; Lipka, Melanie; Muharemovic, N; Meinel, D; Vehring, S; Boeck, G; Kempf, M; Pavlovic, B; Schmueckle, F; Phung, G; Huhn, M (MikroSystemTechnik Kongress 2017, 2017)
lhft_intern.bib::Lipka2017

Nanojet 3D Printed Coplanar Waveguides on Flexible Polyimide Substrate up to 24 GHz - Lomakin, Konstantin; Ankenbrand, Markus; Sippel, Mark; Franke, Jörg; Helmreich, Klaus; Gold, Gerald (1st IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS 2019), 2019)
This work proposes an approach for manufacturing of high precision ungrounded coplanar waveguides as high speed interconnections for flexible and wearable sensor as well as IoT systems. Characterization of these printed transmission lines up to a frequency of 24 GHz reveals an insertion loss of up to 8 dB/cm and therefore provides practical advice towards realizable line lengths. Although exhibiting approximately 4 times the attenuation as compared to conventionally manufactured flexible PCB transmission lines, the proposed approach allows for selectively realizing highly precise structures where necessary. Moreover, it is applicable on three-dimensional substrates, such as 3D-MIDs and therefore addresses various future applications.<br

Nearfield imaging probe for contactless assessment of burned skin - Oppelt, Daniel; Pfahler, Tim; Distler, Felix; Ringel, Johannes; Goertz, Ole; Vossiek, Martin (13th European Radar Conference (EuRad), 2017)
In modern burn surgery the fast and precise assessment of the burn depth is challenging but also of high importance to adapt the correct wound care. A contactless nearfield probe operating at frequencies from 75 to 110 GHz is presented that is sensitive to the hydration of the skin layers, which is correlated to the burn depth. The results of an in-vivo human skin measurement are presented and a corresponding simulation is adapted that enables a contactless estimation of hydration of stratum corneum and epidermis/dermis as well as its thickness. A millimeter wave image of ex-vivo burned porcine skin is created by positioning the probe stepwise in front of the target to exemplary illustrate the potential of nearfield probe imaging for burn diagnosi

Near Field mm-Wave Imaging with Multistatic Sparse 2 D-Arrays - Ahmed, S. S.; Schießl, Andreas; Schmidt, Lorenz-Peter (Proceedings of the 6th European Radar Conference, 2009)
A near field application of multistatic 2D sparse arrays designed based on an effective aperture concept is presented. Several test arrays which utilize this concept are introduced along with simulation and measurement results for near field operation at 100 GHz. High reduction in the needed number of transmit and receive modules is verified along with the drawbacks in the image quality. Good agreement between measurements and simulations is demonstrated.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.LEH.nearfi

Near-infrared radiation induced attenuation in nested anti-resonant nodeless fibers - Medaer, Sacha; Bradley, Thomas D.; Francesca, Diego Di; Fu, Qiang; Jasion, Gregory; Kuhnhenn, Jochen; Meroli, Stefano; Poletti, Francesco; Schmauß, Bernhard; Taranta, Austin; Vidiajev, Konstantin; Weinand, Udo; et al. (Optics Letters, 2023)
This Letter reports the first, to the best of our knowledge, spectral radiation induced attenuation (RIA) measurements of nested anti-resonant nodeless hollow-core fibers (NANFs). A 5-tube NANF, alongside a solid-core single-mode radiation resistant fiber (SM-RRF), was irradiated under γ-ray up to 101 kGy (SiO2) and under x-ray up to 241 kGy (SiO2). No RIA was observed in the NANF in the second half of the O-band, the S-band, the C-band, and the L-band. The NANF showed a reduction of absorption bands associated with water and HCl under irradiation. Three new attenuation peaks were radiolytically induced and are attributed to the creation of HNO3. These peaks are centered respectively at 1441 nm, 1532 nm, and 1628 nm, with a full width at half maximum (FWHM) of, respectively, 10 nm, 12 nm, and 12 nm. These results demonstrate that the wide bandwidth range of NANFs is essentially unaffected by radiation, but the internal gas contents of the NANF must be managed to avoid producing undesirable spectral features through radiolytic reactions. Wide spectral regions almost unaffected by the ionizing radiation could open new possibilities for the use of NANF in harsh radiation environments.
CRIS-Team Scopus Importer:2023-12-15

Network based Vehicle-to-Infrastructure and Vehicle-to-Vehicle Localization - Millner, Hendrik; Ebelt, Randolf; Vossiek, Martin (2010 IEEE International Conference on Wireless Information Technology and Systems, Workshop on Innovative Circuits, Systems and Applications for Local Position Estimation, 2010)
lhft_intern.bib::Millner2010

Neuartige Konzepte für die Radarbildgebung in heterogenen Medien - Ullmann, Ingrid (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2021)

Neuartige Verfahren zur Holographische Ortung von UHF RFID Tags - Miesen, Robert; Kirsch, Fabian; Vossiek, Martin (RADCOM 2011 - Workshop, Developer Forum and Exhibition, 2011)
lhft_intern.bib::Miesen2011b

Neue Ansätze für die verteilte kooperative räumliche Lokalisierung in drahtlosen Sensornetzwerken - Ebelt, Randolf (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2014)
UnivIS-Import:2016-07-26:Pub.2014.tech.IE.LEH.neuean

Neural Networks for Microwave Characterization of Arbitrary Shaped Material Samples in Leaky Cavities - Penirschke, Andreas; Schüßler, Martin; Vossiek, Martin; Gulden, Peter; Jakoby, Rolf (German Microwave Conference, GeMiC, 2005)
UnivIS-Import:2015-04-16:Pub.2005.tech.IE.LEH.neural

New Insights into Wideband Synthetic Aperture Radar Interferometry - Mustieles Perez, Victor; Kim, Sumin; Krieger, Gerhard; Villano, Michelangelo (IEEE Geoscience and Remote Sensing Letters, 2024)
Synthetic aperture radar interferometry (InSAR) is a technique that exploits the phase difference between two synthetic aperture radar (SAR) images to generate digital elevation models (DEMs) of the imaged terrain. InSAR has a well-established theoretical background, but approximations for narrowband signals are often made. To unwrap the interferometric phase, dual-baseline techniques are also commonly employed. Modern InSAR systems will use wider bandwidths to improve the accuracy and resolution of the DEMs. This letter generalizes the expressions of the baseline decorrelation and the critical baseline for InSAR systems with wide bandwidths and large baselines, where the spectral shrinkage is not negligible. It is also shown that radargrammetry offers high potential to unwrap the interferometric phase already on a pixel-by-pixel basis. The proposed approach can also exploit acquisitions with multiple baselines or frequency bands. The results show that a single wideband interferometric acquisition may suffice to perform phase unwrapping for high interferometric coherences. The concepts discussed in this paper will help to design and enhance the performance of future wideband and multi-band InSAR missions to deliver a new generation of DEMs with unprecedented resolution and accuracy.
CRIS-Team Scopus Importer:2024-09-20
Keywords: drones; interferometric coherence; multi-band; radargrammetry; SAR interferometry; spectral shift; Synthetic aperture radar (SAR); unmanned aerial vehicle (UAV); wide bandwidth

Nichtlineare Faseroptik: Grundlagen und Anwendungsbeispiele - Engelbrecht, Rainer (Springer Vieweg, 2014)
lhft_intern.bib::engelbrecht15

Noise in homodyne FMCW radar systems and its effects on ranging precision - Thurn, Karsten; Ebelt, Randolf; Vossiek, Martin (IEEE International Microwave Symposium 2013, 2013)
In this paper, a closed-form expression for the ranging uncertainty of a primary frequency-modulated continuous-wave (FMCW) radar is introduced. In addition to basic system parameters also the phase noise profile of the transceiver serves as an input for this novel approach. On the signal processing side, phase noise range correlation effects are taken into account and an estimate for the ranging uncertainty is deduced. Thus, the influence of phase noise on the system performance in terms of precision can be directly predicted. For support of the theory, Monte-Carlo simulations were conducted. Measurement results acquired with a 77 GHz radar system are in good agreement with the theory. © 2013 IEEE.
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.noisei
Keywords: Frequency modulation; Millimeter-wave radar; Phase locked loop; Phase noise; Remote sensing; Signal synthesis

NOLM based DPSK Signal Regeneration - Striegler, Arne; Meißner, Markus; Cvecek, Kristian; Sponsel, Klaus; Leuchs, Gerd; Schmauß, Bernhard (IEEE Photonics Technology Letters, 2005)
We present a nonlinear optical loop mirror (NOLM)-based 2R-regenerator setup, which is capable of regenerating signals modulated in phase-sensitive modulation formats. In a conventional NOLM, fluctuations of the signal amplitude are converted into phase fluctuations. Therefore, it is not suitable for regeneration of signals, modulated in formats such as differential phase-shift keying (DPSK) or duobinary. In this letter, we present a modified NOLM setup for 2R-regeneration taking return-to-zero DPSK as an example. © 2005 IEEE.
UnivIS-Import:2015-03-09:Pub.2005.nat.dphy.optik.1optik.nolmba
Keywords: All-optical regeneration; Differential phase-shift keying (DPSK); Nonlinear optical loop mirror (NOLM)

Non Destructive Complex Permittivity Determination of Glass Material with Planar and Convex Survace - Cenanovic, Amir; Martius, Siegfried; Kilian, A.; Schür, Jan; Schmidt, Lorenz-Peter (6th German Microwave Conference, 2011)
lhft_intern.bib::Cenanovic11

Non-destructive testing of arbitrarily shaped refractive objects with millimetre-wave synthetic aperture radar imaging - Ullmann, Ingrid; Adametz, Julian; Oppelt, Daniel; Benedikter, Andreas; Vossiek, Martin (Journal of Sensors and Sensor Systems, 2018)
Millimetre-wave (mmW) imaging is an emerging technique for non-destructive testing. Since many polymers are transparent in this frequency range, mmW imaging is an attractive means in the testing of polymer devices, and images of relatively high resolution are possible. This contribution presents an algorithm for the precise imaging of arbitrarily shaped dielectric objects. The reconstruction algorithm is capable of automatically detecting the object's contour, followed by a material-sensitive reconstruction of the object's interior. As an example we examined a polyethylene device with simulated material defects, which could be depicted precisel
lhft_intern.bib::Ullmann18b

Non-destructive testing of glass fibre reinforced plastics with a full polarimetric imaging system - Nezadal, Martin; Schür, Jan; Schmidt, Lorenz-Peter (Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2014 39th International Conference on, 2014)
A full polarimetric imaging system for the nondestructive testing of glass fibre reinforced plastics in the W-Band (75 GHz to 110 GHz) is presented. It is capable of detecting defects in depths of up to 14.5mm, and 0.5mm near the backside of the samples. The full polarimtric information eases the defect detection, since it is not sensitive for the reflection from the backside.
lhft_intern.bib::NezadalIRMMW14

Non-destructive testing of glass fibre reinforced plastics with a synthetic aperture radar in the lower THz region - Nezadal, Martin; Schür, Jan; Schmidt, Lorenz-Peter (Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2012 37th International Conference on, 2012)
The non-destructive testing (NDT) of glass fibre reinforced plastics (GFRP) becomes more and more important. A test setup using a synthetic aperture radar (SAR) at frequencies of 220 - 325 GHz was set up to detect artificial defects in the probe. The paper will present experimental results and will furthermore address the challenges of imaging GFRP samples in a reflection geometry setup. © 2012 IEEE.
UnivIS-Import:2015-04-16:Pub.2012.tech.IE.LEH.nondes

Non-linear compensation by optimized digital backward propagation - Lin, Chien-Yu; Asif, Rameez; Schmauß, Bernhard (ITG Fachtagung Photonische Netze, 2012)
lhft_intern.bib::Lin2012a

Nonlinearity and Phase Noise Mitigation Using Feed-forward Carrier Phase Estimation and Digital Backward Propagation in Coherent QAM Transmission - Pakala, Lalitha; Schmauß, Bernhard (Physics Procedia, Proceedings of the 8th International Conference on Laser Assisted Net Shape Engineering (LANE 2014), 2014)
We numerically investigate the performance of Viterbi-Viterbi (VV) carrier phase estimation (CPE) and feed-forward decision directed (DD) CPE along with digital backward propagation (DBP) to mitigate laser phase noise, linear and nonlinear fiber impair- ments for polarization multiplexed (PM) 4 and 16-ary quadrature amplitude modulation (QAM) coherent systems. For 16-QAM, DD-CPE is compared with quadrature phase shift keying (QPSK) partitioning method that is based on the modification of VV-CPE. When the laser phase noise is negligible, both CPE methods exhibit a similar performance when employed after DBP. However, in the presence of phase noise, non-decision directed VV-CPE (for 4-QAM) and QPSK partitioning (for 16-QAM) methods outper- form DD-CPE with greater phase noise tolerance and reduced complexity.
lhft_intern.bib::Pakala2014c

Nonlinear Mitigation using Carrier Phase Estimation and Digital Backward Propagation in Coherent QAM Transmission - Lin, Chien-Yu; Asif, Rameez; Holtmannspötter, Michael; Schmauß, Bernhard (Proceedings of the 38th European Conference and Exhibition on Optical Communication (ECOC), 2012)
We investigate the performance of carrier phase estimation (CPE) and digital backward propagation (DBP) in compensating fiber nonlinearity for 224Gbps polarization-multiplexed quadrature-amplitudemodulation coherent systems with level of 4 and 16 (PM-4-QAM and PM-16-QAM) over standard single-mode fiber (SSMF) uncompensated link. The results from numerical simulation show the individual performance of CPE and DBP as well as their mutual influence. With DBP compensation, required CPE tap number for optimal performance can be reduced by 50% for 4-QAM signal and 67% for 16-QAM signal compared to linear compensation. On the other hand, employing CPE compensation after DBP also allows to reduce DBP steps. In the mentioned PM-16-QAM system, 60% reduction in the required number of DBP steps to achieve BER=10-3 is possible, with a step-size of 200km, which reveals great potential to reduce the complexity for future real time implementation. © 2012 Optical Society of Americ
UnivIS-Import:2017-12-18:Pub.2012.tech.IE.LEH.nonlin

Nonlinear mitigation using carrier phase estimation and digital backward propagation in coherent QAM transmission. - Lin, Chien-Yu; Asif, Rameez; Holtmannspötter, Michael; Schmauß, Bernhard (Optics Express, 2012)
We investigate the performance of carrier phase estimation (CPE) and digital backward propagation (DBP) in compensating fiber nonlinearity for 224 Gbps polarization-multiplexed quadrature-amplitude-modulation coherent systems with level of 4 and 16 (PM-4-QAM and PM-16-QAM) over standard single-mode fiber (SSMF) uncompensated link. The results from numerical simulation show the individual performance of CPE and DBP as well as their mutual influence. With DBP compensation, required CPE tap number for optimal performance can be reduced by 50% for 4-QAM signal and 67% for 16-QAM signal compared to linear compensation. On the other hand, employing CPE compensation after DBP also allows to reduce DBP steps. In the mentioned PM-16-QAM system, 60% reduction in the required number of DBP steps to achieve BER=10(-3) is possible, with a step-size of 200 km, which reveals great potential to reduce the complexity for future real time implementation.

Non-linear Mitigation Using Carrier Phase Estimation and K-Means Clustering - Pakala, Lalitha; Schmauß, Bernhard (ITG Fachtagung Photonische Netze, 2015)
We investigate the non-linear mitigation performance of modulation format independent or universal carrier phase estimation (U-CPE) along with K-Means clustering (KMC) algorithm for a 28 Gbaud/s polarization multiplexed (PM) 16 quadrature amplitude modulation (16-QAM) coherent transmission system. Numerical simulations on transmission performance prove that the U-CPE outperforms decision directed carrier phase estimation (DD-CPE) with a gain of 1 dB and non-linear tolerance of approximately 2 dB. Furthermore, it has been verified that a gain of 0.3 dB in both linear and non-linear regimes can be obtained by employing KMC after U-CPE. In addition, the benefit acquired from the combined use of the afore-mentioned algorithms has been also investigated in the presence of laser linewidth effects in addition to fiber non-linearity as well as increasing the feedback delay of U-CPE up to 50 symbol periods to realize the feasibility for real-time implementations. Besides single channel systems, the algorithms have also been employed for wavelength division multiplexing (WDM) systems with 50 GHz channel spacing to see the impact of cross phase modulation (XPM) on their performance. Numerical investigations show that the gain obtained from K-Means algorithm starts vanishing as the XPM effect becomes stronger with an increase in the number of WDM channels.
lhft_intern.bib::Pakala2015a

Nonlinear Phase Noise Compensation Using a Modified Nonlinear Optical Loop Mirror - Sponsel, K.; Stephan, C.; Onishchukov, G.; Schmauß, Bernhard; Leuchs, Gerd (OSA Optics and Photonics Congress, Advanced Photonics, BGPP Topical Meeting, Karlsruhe, 21.-24. Juni, 2010)
lhft_intern.bib::Sponsel10

Nonlinear Phase Noise Reduction in a DPSK Transmission System Using Cascaded Nonlinear Amplifying Loop Mirrors - Stephan, Christian; Sponsel, Klaus; Onishchukov, Georgy; Schmauß, Bernhard; Leuchs, Gerd (IEEE Photonics Technology Letters, 2009)
The performance of a nonlinear amplifying loop mirror as a phase-preserving amplitude 2R regenerator in a differential phase-shift-keying transmission system with nonlinear phase noise as dominant limiting effect has been investigated in a recirculating fiber-loop setup. The experimental results show that cascaded regenerators can efficiently prevent the accumulation of nonlinear phase noise in such systems. It was possible to significantly increase the transmission quality; alternatively, a considerable increase of fiber launch power could be achieved for the same bitor ratio. As a limiting effect, the amplified Rayleigh backscattering in the highly nonlinear fiber is identified when the regenerator is passed multiple times. © 2009 IEEE.
UnivIS-Import:2015-03-09:Pub.2009.nat.dphy.optik.1optik.nonlin
Keywords: 2r regeneration; Differential phase-shift keying (DPSK); Nonlinear amplifying loop mirror (NALM); Nonlinear phase noise

Nonlinear Phase-Shift Compensation by a Nonlinear Amplifying Loop Mirror - Schmauß, Bernhard; Sponsel, Klaus; Stephan, C.; Onishchukov, Georgy; Leuchs, Gerd (Conference on Lasers and Electro-Optics CLEO, Paper JThE59, San Jose, May, 2010)
The nonlinear amplifying loop mirror as a nonlinear phase-shift compensator for multilevel phase-encoded optical signals is considered. Simulations of a 20 Gb/s DQPSK transmission system showed a significant BER improvement for post-compensation.
lhft_intern.bib::Schmauss10a

Non-mydriatic, 68 wide fundus imaging with low cost components - Höher, Bernhard; Köhler, Aaron; Schmauß, Bernhard; Michelson, Georg (ARVO Annual Meeting 2012, 2012)
lhft_intern.bib::Hoeher2012a

Non-mydriatic, wide field, fundus video camera - Höher, Bernhard; Voigtmann, Peter; Michelson, Georg; Schmauß, Bernhard (SPIE Photonics West, 2014)
We describe a method we call "stripe field imaging" that is capable of capturing wide field color fundus videos and images of the human eye at pupil sizes of 2mm. This means that it can be used with a non-dilated pupil even with bright ambient light. We realized a mobile demonstrator to prove the method and we could acquire color fundus videos of subjects successfully. We designed the demonstrator as a low-cost device consisting of mass market components to show that there is no major additional technical outlay to realize the improvements we propose. The technical core idea of our method is breaking the rotational symmetry in the optical design that is given in many conventional fundus cameras. By this measure we could extend the possible field of view (FOV) at a pupil size of 2mm from a circular field with 20° in diameter to a square field with 68° by 18° in size. We acquired a fundus video while the subject was slightly touching and releasing the lid. The resulting video showed changes at vessels in the region of the papilla and a change of the paleness of the papilla. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use onl
lhft_intern.bib::Hoeher2014

Novel 24 GHz FMCW front-end with 2.45 GHz SAW reference path for high-precision distance measurements - Nalezinski, Martin; Vossiek, Martin; Heide, Patric (IEEE MTT-S International Microwave Symposium, 1997)
A new 24 GHz non-linear FMCW radar is reported, which features a high-precision 2.45 GHz SAW (Surface Acoustic Wave) reference and adaptively compensates for phase errors by software. Kernel functions are implemented at a 2.45 GHz IF level reducing the expense of critical RF components in order to realize a fully planar front-end.
UnivIS-Import:2015-04-16:Pub.1997.tech.IE.LEH.novel2

Novel 24 GHz radar level gauge for industrial automation and process control. Ein neues 24 GHz Radar-Füllstandsmessgerät für die industrielle Automation und Prozeßüberwachung. - Vossiek, Martin; Heide, Patric; Nalezinski, Martin; ens, W.; Fiebelkorn, K. D.; Oreans, L. (9. Internationale Fachmesse für Sensoren, Messaufnehmer und -systeme, Sensor 99, 1999)
UnivIS-Import:2015-04-16:Pub.1999.tech.IE.LEH.novel2

Novel approaches for RFID/transponder localization based on aperture synthesis - Vossiek, Martin; Li, Gang; Miesen, Robert; Parr, Andreas (IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, 2015)
lhft_intern.bib::Vo2015icmem

Novel Chipless RFID Concept with High Data Capacity - Ullmann, Ingrid; Root, Konstantin; Vossiek, Martin (IEEE/MTT-S International Microwave Symposium (IMS), 2021)
We propose a new concept for passive RFID tags and an associated reading and decoding strategy. The information is encoded in the orientation of small wires inside the tag. A circular polarization millimeter-wave imaging system is used as an inter-rogation unit. Decoding is achieved by reconstructing a radar im-age of the tag and using the Hough transform to determine the wires’ orientations. We demonstrate the first-ever use of multi-layer image-based RFID tags. According to our results, up to four layers can be used. An information content of 251 bit (7 bit/cm2) was obtainable, which is unprecedented in image-based RFID. <

Novel control loop concept for direct distance measurement using photonic mixing devices (PMD) - Becker, Dirk; Gulden, Peter; Vossiek, Martin; Schwarte, R. (OPTO, Internat. Conf. and Exhibition on Optoelectronics, Optical Sensors & Measuring Techniques / Optische Sensorik, Meßtechnik & Elektronik, 2002)
UnivIS-Import:2015-04-16:Pub.2002.tech.IE.LEH.novelc

Novel Coupled Microstrip Wideband Filters with Spurious Response Suppression - Rehner, Robert; Schneiderbanger, Dirk; Sterns, Michael; Martius, Siegfried; Schmidt, Lorenz-Peter (European Microwave Conference 9-12. Oct., 2007)
Wideband coupled line filters with spurious response suppression (2f 0) in the millimeter wave range are reported. The first filter exhibits a relative bandwidth of 62% with a return loss better than 20 dB and a suppression of the second spurious passband of more than 40 dB. The very high necessary couplings to achieve that large bandwidth in combination with the spurious suppression are realized by removing partially the ground metallization beneath the proposed coupling sections. The filters are directly compatible to microstrip circuits without the need for complicated transitions. They do not require techniques like substrate suspension or dielectric overlay to match the evenand odd-mode phase velocities, but are realizable on a classical substrate with ground. Further, simulation and measurement results of a second, high selective filter (11th order) with an even higher bandwidth of 78% are shown. Measurement and simulation results are fitting very well. © 2007 EuMA.
UnivIS-Import:2015-04-16:Pub.2007.tech.IE.LEH.novelc

Novel Design Approach for Ultra Compact, High Rejection LTCC Balanced Filter - Yatsenko, Andriy; Heyen, Johann; Sevskiy, Georgiy; Heide, Patric; Vossiek, Martin (38th European Microwave Conference (EuMC2008), 2008)
In this paper a new approach for miniaturizing multilayer LTCC designs (Low Temperature Co-Fired Ceramics is proposed. Using the stacking options inside LTCC more consequently, a new very compact high-rejection balanced bandpass filter for WirelessLAN (based on IEEE 802.11a standard) is realized. The demonstrated filter performance is a very promising. With only 2.7 dB insertion loss in the band of interest and excellent out-of-band attenuation it occupies area less than 1.8 mm2. Compared to designs with the same dielectric constant this downsizes by factor of two the required area without degrading the performance. The correlation between measurement and simulation results is a very good. © 2008 EuMA.
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.noveld

Novel Dielectric Waveguide Design Studies for mmW Applications - Distler, Felix; Vossiek, Martin; Schür, Jan (2018 ASIA-PACIFIC MICROWAVE CONFERENCE PROCEEDINGS (APMC), 2018)
CRIS-Team WoS Importer:2019-02-22

Novel FMCW radar system concept with adaptive compensation of phase errors - Vossiek, Martin; Heide, Patric; Nalezinski, Martin; Magori, V. (26th European Microwave Conference, EuMC, 1996)
A new high-performance FMCW sensor system concept is presented. The approach is based on an adaptive signal processing scheme compensating phase errors caused by VCO phase noise as well as the non-linearity of the frequency modulation. The key component of the low-cost sensor is a SAW (surface acoustic wave) delay line representing a miniaturised high-precision radar reference path. A correction algorithm equalises the target signal according to the phase errors simultaneously measured with the reference path. Employing this method, an excellent range resolution as well as a high dynamic range and multi-target selectivlty is obtained, which has been experimentally demonstrated at millimetrewave frequencies. © 1996 IEEE.
UnivIS-Import:2015-04-16:Pub.1996.tech.IE.LEH.novelf

Novel Fully Electronic Active Real-Time Millimeter-Wave Imaging System based on a Planar Multistatic Sparse Array - Ahmed, Sherif Sayed; Schießl, Andreas; Schmidt, Lorenz-Peter (International Microwave Symposium 2011, 2011)
The interest on active millimeter-wave and microwave imaging systems is increasing nowadays due to their utilization in security, medical, and industrial applications. Imaging systems using monostatic arrays suffer from the high number of antenna positions, making a fully electronic solution very costly and impractical. Multistatic arrays, however, offer the chance for high reduction factors in the number of antennas, and then allow for fully electronic solutions. Here, a new array architecture is presented, which is suitable for real-time operation and is capable of delivering high image quality in means of resolution and dynamic range. An example array is demonstrated for operation from 72 to 80 GHz. The imaging system hardware is introduced, along with imaging results of human
lhft_intern.bib::Ahmed11

Novel heterodyne 24 GHz FMCW radar front-end with high-precision 2.45 GHz SAW reference path - Nalezinski, Martin; Sczesny, O.; Vossiek, Martin; Heide, Patric (9. MIOP, Mikrowellen und Optronik, Kongreßmesse für Höchstfrequenztechnik, 1997)
UnivIS-Import:2015-04-16:Pub.1997.tech.IE.LEH.novelh

Novel Localization and Transponder Techniques for Backscatter RFID-Tags - Vossiek, Martin; Max, Stephan (EEEfCOM 2008, 2008)
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.novell

Novel Localization Concepts with Advanced Low-Complexity Microwave and Millimeterwave RFIDs - Carlowitz, Christian; Vossiek, Martin (IMS 2017 Workshop on Localization in Wireless Sensor Networks, 2017)

Novel Microwave Vibration Monitoring System for Industrial Power Generating Turbines - Wagner, M.; Schulze, A.; Vossiek, Martin; Stephelbauer, Carl; Weigel, Robert; Vortmeyer, N.; Heide, Patric (1998 IEEE MTT-S International Microwave Symposium Digest, 1998)
A novel microwave sensor system for real-time monitoring of turbine blade vibrations is reported. The self-calibration of the sensor modules, a key feature of the implemented concept, is based on adaptive frequency tuning of the microwave source. By using this calibration, degradation of the measurement performance caused by temperature drift and dirt deposit is compensated. During pilot runs with a 65 MW gas turbine the microwave system proved to give excellent measurement results.
elib2cris::1512001600,wagner1998

Novel nonlinear FMCW radar for precise distance and velocity measurements - Vossiek, Martin; von Kerssenbrock, T.; Heide, Patric (IEEE MTT-S International Microwave Symposium, 1998)
A new nonlinear FMCW radar concept for precise distance and velocity measurements is presented. The radar system incorporates a surface acoustic wave (SAW) reference device used for an online detection of oscillator phase errors. With a specific Doppler/distance ambiguity function, that is continuously adapted to the measured phase error, the target signal is evaluated. By applying this novel technique the optimal distance resolution at a given sweep bandwidth is obtained independently of the Doppler resolution. The proposed system approach has been evaluated with a 77 GHz radar incorporating a flip-chip MMIC VCO.
UnivIS-Import:2015-04-16:Pub.1998.tech.IE.LEH.noveln

Novel opportunities for optical level gauging and 3D-imaging with the photoelectronic mixing device - Gulden, Peter; Vossiek, Martin; Heide, Patric; Schwarte, R. (18th IEEE Instrumentation and Measurement Technology Conference. Rediscovering Measurement in the Age of Informatics, 2001)
The novel Photoelectronic Mixing Device (PMD) possesses a variety of unique characteristics that open up new fields for optical distance measurement technology. PMD devices for the first time allow the use of straightforward modulation and system concepts previously constrained to radar and ultrasonic systems. This paper first reviews the PMD principle and then points out the differences between conventional optical systems and PMD systems. The requirements of two different applications, level gauging and 3-D object position measurement, are discussed. Suitable system concepts are introduced and verified with experiments. The results prove the feasibility of single pixel sensors capable of high accuracy and multi-target resolution as well as low cost 3-D imaging systems.
UnivIS-Import:2015-04-16:Pub.2001.tech.IE.LEH.novelo
Keywords: Level gauging; Optical distance measurement; Photoelectronic mixing device (PMD); Time-of-flight

Novel opportunities for optical level gauging and 3D-imaging with the photoelectronic mixing device - Gulden, Peter; Vossiek, Martin; Heide, Patric; Schwarte, R. (IEEE Transactions on Instrumentation and Measurement, 2002)
UnivIS-Import:2015-03-09:Pub.2002.tech.IE.LEH.novelo_2

Novel optical distance sensor based on MSM technology - Gulden, P; Becker, D; Vossiek, Martin (IEEE Sensors 2002. First IEEE International Conference on Sensors, 2002)
This paper describes a novel distance-sensor concept based on photodiodes in metal-semiconductor-metal technology (MSM). MSM photodiodes can be operated as opto-electronic mixers (OEM) functioning similar to the so-called photonic mixing device (PMD). This paper employs the correlation techniques previously used with the PMD to the MSM. First experimental results obtained with the MSM inserted into the authors' standard lab setup previously used for PMD testing are provided Additionally different configurations well suited for mixer operation of the MSM are pointed out. Throughout this paper, the similarities of PMD and MSM are pointed out as well as the key difference
lhft_intern.bib::Gulden2002a

Novel optical distance sensor based on MSM technology - Gulden, Peter; Becker, Dirk; Vossiek, Martin (IEEE Sensors Journal, 2004)
This paper describes a novel distance-sensor concept based on photodiodes in metal-semiconductor-metal technology (MSM). MSM photodiodes can be operated as electrooptical mixers functioning similar to the so-called photonic mixing device (PMD). This paper employs the correlation techniques previously used with the PMD to the MSM. First, experimental results obtained with the MSM inserted into the authors' standard laboratory setup are provided. Additionally, different configurations well suited for mixer operation of the MSM are pointed out. Throughout this paper, similarities between the PMD and MSM are pointed out, as well as key differences.
UnivIS-Import:2015-03-09:Pub.2004.tech.IE.LEH.novelo_4
Keywords: Electrooptical mixer; Metal-semiconductor-metal technology (MSM); Optical intensity-modulation (IM) time-of-flight (TOF) distance measurement; Photonic mixing device (PMD)

Novel Optical Measurement Technology for Shock Waves in Lithotripsy - Granz, B.; Nanke, R.; Fehre, J.; Pfister, T.; Engelbrecht, Rainer; Schulz, R. (European Urology Supplements, 2004)
UnivIS-Import:2015-03-09:Pub.2004.tech.IE.LEH.novelo

Novel optical time-of-flight distance sensor concepts based on MSM and PMD technology - Gulden, Peter; Becker, Dirk; Vossiek, Martin (IRS / GRS, Internat. Radarsymp./German Radar Symp., DGON, 2002)
UnivIS-Import:2015-04-16:Pub.2002.tech.IE.LEH.novelo

Novel Passive Calibration Method for Fully Polarimetric Near Field MIMO Imaging Radars - Körner, Georg; Oppelt, Daniel; Adametz, Julian; Vossiek, Martin (GeMiC 2019 - 2019 German Microwave Conference, 2019)
In this paper a novel method for calibration of multiple-input multiple-output (MIMO), fully polarimetric near field radar systems is presented. The developed approach allows for the first time a practical and effective calibration, i.e. the correction / equalization of the frequency transfer function of all polarimetric radar channels even in a near field scenario where the target distance is not large compared to the MIMO antenna array dimension. In a first step, the mutual coupling between all channels is corrected by an empty space measurement. The polarimetric calibration is based on measurements with two simple, passive calibration standards. An offset short calibration of the co-polarized channels is conducted by using a mirroring reflection of a plane metal plate. A dihedral reflector is employed for the calibration of the cross-polarized channels. Since the dihedral reflection is distinctly directive and due to the close range acquisition condition, only channels with adjacent antenna elements can contribute to the calibration process. However, it is shown in this paper, that the sparse calibration data obtained from these few antenna combinations are sufficient for a successive calibration of all cross-polarized channels. This way, the novel method allows for a simple but yet effective calibration of fully polarimetric high resolution near field imaging MIMO radars based on two cost-efficient passive standards and with very low adjustment efforts during the calibration.
CRIS-Team Scopus Importer:2019-05-21
Keywords: millimeter-wave radar; MIMO radar; Multistatic radar; polarimetric synthetic aperture radar; synthetic aperture radar

Novel Radar-based Calibration Techniques for Massive MIMO Arrays - Carlowitz, Christian; Gröschel, Patrick; Schober, Robert; Vossiek, Martin (IMS 2017 Workshop on Massive MIMO and its 5G Related Applications, 2017)

Novel Secondary Radar for Precise Distance and Velocity Measurement in Multipath Environments - Röhr, Sven; Gulden, Peter; Vossiek, Martin (4th European Radar Conference, EuRAD, 2007)
The performance of wireless systems strongly depends on the characteristics of the radio channel. Multipath propagation and Doppler effect are two phenomena to be considered. We present a Frequency-Modulated Continuous Wave (FMCW) secondary radar concept to estimate the offset in time and in frequency of two wireless units and to measure their distance to each other. The distance can be measured with a standard deviation as low as 1 cm. However, the accuracy of the system is degraded in multipath environments or if the stations are moving relative to each other. In this paper we show a novel extension of the algorithm to cope with multipath propagation and the Doppler effect. The broadband measurement principle at hand is robust towards multipath interference. Additionally the Doppler effect is compensated for. By evaluating the Doppler frequency shift the relative velocity of the mobile units is measured directly. Measurement results prove the significant improvement in system performance if the extended algorithms are used. © 2007 EuMA.
UnivIS-Import:2015-04-16:Pub.2007.tech.IE.LEH.novels

Novel Tunable Hexaferrite Bandpass Filter Based on Open-Ended Finlines - Sterns, Michael; Rehner, Robert; Schneiderbanger, Dirk; Martius, Siegfried; Schmidt, Lorenz-Peter (IMS 2009, Boston, June, 2009)
In this paper a novel tunable bandpass filter based on open ended finlines is presented. Hexagonal ferrite spheres are used as resonators to cover a tuning frequency range from 39GHz to 68GHz. The measured insertion loss of the filter varies from 5.3dB to 7dB with a typical 3dB-Bandwidth between 300MHz and 400MHz. An off-resonance isolation of about 60dB is achieved although only two spheres are used. By employing finlines for the external coupling of the resonator spheres, broadband transitions to microstrip line can be designed easily, thus simplifying the integration into a planar transmission line environment. Furthermore, the use of finlines allows to cover a considerably larger operating range than the classical rectangular waveguide based coupling structures do. © 2009 IEEE.
UnivIS-Import:2015-04-16:Pub.2009.tech.IE.LEH.novelt

Novel Tunable Hexaferrite Bandpass Filter Based on Rectangular Waveguide Coupled Shielded Coplanar Transmission Lines - Sterns, Michael; Schneiderbanger, Dirk; Rehner, Robert; Martius, Siegfried; Schmidt, Lorenz-Peter (IEEE MTT-S International Microwave Symposium June, 2008)
In this paper a novel tunable high isolation bandpass filter is presented. The filter consists of two shielded coplanar transmission lines coupled by a rectangular waveguide. Hexagonal ferrite spheres are used to cover a tuning frequency range from 50 to 80GHz. Measurement results up to 69GHz are shown. The measured insertion loss of the filter lies between 7.1 and 9.3dB. An off-resonance isolation better than 60dB is achieved what is extraordinarily high for a two spheres filter. The typical 3dB-bandwidth is about 250MHz. As planar transmission lines are used, the filter can be integrated into a coplanar or microstrip environment easily what is advantageous for the construction of highly integrated modules. The operating frequency range can be expanded up to 80GHz by replacing the 1.85mm-connectors by lmm-connectors or using other suitable waveguide transitions, thus covering considerably more bandwidth than rectangular waveguide based coupling structures. © 2008 IEEE.
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.novelt