Investigation of a compact antenna diversity set for satellite radio applications

Antenna diversity sets are presented for mobile reception of satellite digital radio signals in the S-band. Different antenna types are combined to antenna diversity sets with an overall size comparable to a conventional single antenna. Measurements results of the reflection coefficient and the mutual coupling between the antennas are shown. An improved radiation pattern is achieved by phase shifting and combining of independent radiation pattern from two antenna types. The radiation pattern of the single antennas and the resulting radiation pattern of the antenna diversity sets are investigated and measured. The resulting radiation pattern shows a considerably higher gain compared to a single antenna. Due to the low mutual coupling between the antennas, they are well suited for combination in a two or three antenna diversity set in switching or maximum-ration combining diversity system. Reception quality can be improved considerably in Rayleigh fading scenarios. The investigated antenna diversity sets are optimized for automotive application where low profile antennas are required.