A fast switching antenna diversity system for improved mobile reception of digital radio signals of a geostationary satellite

In severe multipath propagation scenarios - as for example underneath dense foliage or between buildings - the mobile reception of satellite digital audio radio services (SDARS) can be severely impaired. Antenna diversity is able to increase reception in such scenarios and to increase the link margin of satellite signal transmission. In this contribution a scan-phase antenna diversity system is shown which can be realised with low hardware effort, using only one RF cable between the antenna module and the radio. For radio services where the receivers are already fixed, the antenna diversity system is arranged in a way, that the diversity function is performed completely inside the antenna module. For radio services where the radio can be modified, parts of the diversity function can be integrated into the digital signal processing unit of the radio. The two versions of scan-phase diversity are discussed and investigated for the test case of signals which are transmitted from a geostationary satellite. Also a comparison between two different phase shifter resolutions is done in real scenario test drives. Measurement results show that a significant improvement of reception quality is achieved reducing audio mutes by a factor of 20.