Antenna module with integrated scan-phase antenna diversity system for SDARS

A scan-phase multi-antenna diversity system is able to significantly improve reception performance of satellite digital audio radio systems (SDARS) in severe multipath propagation scenarios. The low hardware cost of such a system can only be achieved if a single level measurement circuitry is used for all antenna signals. In this paper the influences of switching between the antenna signals for level detection and the signal processing in the diversity system are studied for two different antenna diversity systems. A modification of the diversity hardware that avoids those influences is investigated. Measurements were performed to compare the modified and unmodified system in terms of audio availability. Test drives underneath dense foliage were conducted with a scan-phase antenna diversity system in combination with a diversity antenna set mounted on the dashboard of a car. This mounting position is of wide interest for example for convertibles, where the car roof is not available for the mounting of SDARS antennas. Measurement results show that the scan-phase antenna diversity system performs very well in such a disadvantageous antenna position. The diversity combination on the dashboard can compete with a roof-mounted patch antenna in the reception of geostationary satellite signals even with a closed roof.