A Diversity Circuit for Investigation of Multi Antenna Transmission and Reception in Car-to-Car and Car-to-X Communication

For Car-to-Car and Car-to-X applications a new microwave circuit for multi-antenna-applications is presented. Up to four antenna signals are combined via microwave switches and phase shifters with a level detection unit and a microcontroller. The multi-antenna-circuit is realized in a hardware demonstrator, serving as a platform for investigation of different diversity concepts for up to four antennas. Its components and circuit parts are shown by way of simulation and measurement. A first example of application is presented where the microwave circuit platform is tested together with an equal-phase diversity algorithm in a two channel test bed in a bad urban Rayleigh fading scenario. Even for the example of only two antenna paths a reduction of fading time by a factor of four and an average increase of SNR by 3 dB can be shown.