MEMS-based switched diversity antenna at 2.3 GHz for automotive applications

Our previous work is presented on diversity antenna experiments in the 2.3 GHz band, specifically for applications in the automotive environment. We describe the case of two-element position diversity, and we study the effects of the antenna positions on the amount of diversity gain. The presentation consists primarily of measurement data on a moving vehicle, with software post-processing to determine the effects of diversity combining. We present several diversity combining schemes, and describe a switched diversity circuit that we have built to address one of these schemes. An in-house developed SPDT MEMS switch, which has desirable insertion loss and isolation characteristics for the diversity switch, is shown. Also, a discussion on using a switch for the switched diversity antenna is included.