Experimental Study of the Retrodirective Antenna Array System in a Multipath Environment

The concept of retro directive arrays was originated decades ago and various system architectures associated with it have been studied and developed in the past several years. However, the focus of the research so far has been on implementation algorithms and potential applications; although the retrodirective systems have been proposed for uses in communications, little has been carried out in evaluation of its communication performance metric. In this work, we first developed the software radio based retrodirective system and then placed it under test for its communication performance in an indoor environment that is rich of multipath. The test results demonstrate for the first time that the retrodirective system has superior performance in the two important performance parameters, the error-vector- magnitude (EVM) and bit-error-rate (BER). In a non-line-ofsight environment, the BER performance of a four-element retrodirective system can be three decades over that of a single antenna element system and two decades better than that of a conventional non- retro directive array system with the same number of antenna elements.