Receiver structures of ESPAR antenna to realize receive diversity

In this paper, we propose receiver structures to achieve receive diversity which uses ESPAR (Electronically Steerable Passive Array Radiator) antenna. By applying a sinusoidal voltage to the parasitic element of the antenna, we can receive the received signals which have three different central frequencies and experience independent fading. Instead of the conventional idealized complex-valued voltage, we introduce to apply feasible real-valued voltage to the variable reactance element. To receive all the signal components with minimum additional operations and obtain higher diversity gain, we propose three receiver structures. According to the evaluation of BER (Bit Error Rate) performances, we can obtain almost the same diversity gain by a receiver structure as that by the receiver with idealized applying voltage.