A Multilayer Reconfigurable Transmitarray in K-Band for Beam Steering Applications
Frank M, Weigel R, Kölpin A (2017)
Publication Language: English
Publication Status: Published
Publication Type: Conference contribution, Conference Contribution
Future Publication Type: Conference contribution
Publication year: 2017
Event location: Verona
DOI: 10.1109/ICEAA.2017.8065361
Abstract
There are many different radar applications which require a change in the direction of the radiation beam, for example in order to separate signals coming from different directions or to track targets. A change in the main beam direction is usually realized by a mechanical rotation of the antenna or electronically by using phased array systems.
The work presented in this paper is focused on a less common approach to realize beam steering functionality, the so called transmitarray.
The transmitarray is built of several unit cells and is placed in front of a focal source. Each unit cell includes two radiation structures to receive the signal coming from the source on one side and to retransmit it on the other side with a distinct phase shift. The superposition of the signal contributions of all array elements leads to a certain radiation pattern of the whole structure. By individually adjusting the phase shifts of each unit cell the desired radiation pattern can be realized.
The realization of a transmitarray can be done in two steps. First the design of a unit cell which provides the capability of performing the phase shifts has to be done. Afterwards the array synthesis is done by combining several unit cells.
The unit cell used in this approach is derived from previous research with significant improvements and is supposed to work in the 24 GHz ISM band. A continuous phase range is obtained by loading patches with varactor diodes on the outer layers of a layer stack consisting of two thin laminates of RO4350 and a metal sheet in between. Both, metal sheet and second metal layer of the laminate have apertures inside to provide coupling from one patch to the other. By applying a voltage difference between patch and ground plane the capacity of the varactor diode is changed. This detunes the whole structure and leads to a change in the transmission phase. To obtain the desired continuous phase range of 360° several unit cells are placed in series resulting in a multilayer structure.
The functionality of the designed unit cell has been verified in simulation and measurement.
In the next step a 5 x 1 array has been synthesized and designed for a +/- 30° beam steering range with CST MWS. Measurements of the radiation pattern for several combinations of the five tuning voltages have been performed with a measurement setup consisting of two horn antennas and a rotation stage.
A +/- 30° beam steering range has been successfully confirmed.
The designed transmitarray at 24 GHz differs from previous approaches by combining a continuous phase range of the unit cells with a working frequency in the K-band.
Authors with CRIS profile
Martin Frank
Lehrstuhl für Technische Elektronik
Robert Weigel
Lehrstuhl für Technische Elektronik
Alexander Kölpin
Lehrstuhl für Technische Elektronik
Related research project(s)
How to cite
APA:
Frank, M., Weigel, R., & Kölpin, A. (2017). A Multilayer Reconfigurable Transmitarray in K-Band for Beam Steering Applications. In Proceedings of the International Conference on Electromagnetics in Advanced Applications (ICEAA 2017). Verona, IT.
MLA:
Frank, Martin, Robert Weigel, and Alexander Kölpin. "A Multilayer Reconfigurable Transmitarray in K-Band for Beam Steering Applications." Proceedings of the International Conference on Electromagnetics in Advanced Applications (ICEAA 2017), Verona 2017.
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