Multilayer technology for smart antennas in user terminals

Abstract

Antennas with intelligent beamforming and beam steering enhance the overall system performance of future satellite systems for navigation and communication. The generation of multiple independent beams facilitates the use of SDMA and the simultaneous tracking of different satellites to guarantee reliable communication channels free from interference for any satellite constellation and terminal position. For jammer suppression and reduction of multipath propagation effects, definite nulling and side lobe attenuation can be used. Two different terminal antennas with digital beamforming (DBF) and planar radiators are developed. One antenna is used for demonstration purposes and operates in L-band to receive communication signals. The other one, designed for future navigation systems in C-band, has already been fabricated as a breadboard model and was successfully tested [1]. The integration of antenna elements, active RF-devices and digital signal processing requires a multilayer structure. Ground planes in the interfaces ensure proper shielding and well-defined signal propagation along microstrips or striplines. Of special importance therefore are the feeds of the patches for circular polarisation operating in a triplate configuration and the routing of the signal path between different layers.