Reactance diversity: proof-of-concept experiments in an indoor multipath-fading environment with a 5-GHz prototype planar ESPAR antenna

This paper reports the first experiments on binary reactance diversity. A prototype of a 3-element 5-GHz band ESPAR (electronically steerable parasitic array radiator) antenna is designed and fabricated on a planar printed circuit. It consists of one radiator and two parasitic elements with loading varactor diodes. It functions as a diversity antenna with a diversity scheme that employs a simple binary reactance control, based on the criterion of received power. In an indoor multipath-fading environment, the ESPAR antenna exhibits a diversity performance of 7-dB gain at CDF 99% in spite of its simplified mechanics.