Superdirective and Compact Electronically-Beam-Switchable Antenna for Smart Communication Objects

This paper proposes a directive and compact circular array composed of 9 symmetrical radiating elements (1 fed and 8 parasitic elements) with electronically beam-switching capabilities. Thanks to the superdirectivity principle and the use of a floating ground plane, the proposed closely spaced antenna array achieves a maximum realized gain of 4 dBi steered in 8 directions on the horizontal plane. The proposed antenna operates at 868 MHz with a maximum directivity of 8.5 dBi and achieving a 1-dB directivity bandwidth of 10 MHz.