A technique for antenna configuration selection for reconfigurable circular patch arrays

This paper demonstrates a method that allows reconfigurable multi element antennas to select the antenna configuration at the receiver of a Multiple Input Multiple Output (MIMO) communication system. This antenna configuration selection scheme consists of using spatial correlation and average Signal to Noise Ratio (SNR) information to select the antenna radiation pattern at the receiver. We show that using this approach it is possible to achieve capacity gains in a multi element reconfigurable antenna system without modifying the data frame of a conventional MIMO system. We demonstrate our configuration selection algorithm through an analysis of reconfigurable circular patch antennas in realistic MIMO clustered channel models. Using this approach we also show that the functionality of the proposed selection scheme is connected to antenna parameters such as radiation efficiency, input impedance, the level of diversity between the radiation patterns of different antenna configurations, and the average system SNR. The capacity gain achievable with this configuration selection approach is calculated through numerical simulations using reconfigurable circular patch antennas at the receiver of a MIMO system that employs minimum mean square error receivers for channel estimation. The performance of the proposed method is compared to that of a MIMO system that estimates the channel transfer matrix for each antenna configuration in order to select the optimal receiver antenna radiation pattern. Channel capacity and Bit Error Rate (BER) results show the improvement offered by the proposed selection scheme relative to a conventional antenna selection technique for reconfigurable MIMO systems; in particular we show that the improvement increases with the number of configurations in the multi element reconfigurable antenna.