A Three-Antenna Compact Micro-Diversity Module for Automotive Satellite Radio Reception

A new compact micro-diversity module is presented which integrates three individual antenna elements underneath a polycarbonate protection cover with a scan-phase antenna diversity circuit for the reception of satellite radio services at 2.3325 GHz. The module itself has a size of 55 mm by 55 mm, being surrounded by a small additional ground plane brim with a size of 75 mm by 75 mm. The overall height of the module including protection cover and metallic cavity is only 26 mm. Its three-antenna set consists of two ring antenna structures working in different modes combined with a monopole with roof capacitance in the center of the rings.The new module has been tested in a strong fading environment near Detroit (USA) showing a significant reduction of audio mutes compared to a single reference antenna reception system. For the two cases of antenna position on the dashboard as well as on the roof edge with a strong tilting angle, the micro-diversity achieves still acceptable mute ratios while the single reference antenna would fail. The results show that the new diversity module offers new mounting positions to the car manufacturer as well as new regions of reception due to additional gain and fast antenna diversity in fading environments.