Compact Metasurface-Based Circularly Polarized Reconfigurable Antenna

Abstract

A circularly polarized (CP) reconfigurable antenna with a compact size is presented in this paper. The proposed antenna can produce a unidirectional beam whose polarization is switchable between left-hand CP and right-hand CP. The proposed design consists of 2 × 2 unit cells as a primary radiating aperture and a switchable CP source. The polarization reconfigurability is achieved by turning ON/OFF two pin diodes. It is noted that the biasing wire and the diodes are positioned in the switchable feeding network rather than the radiating element to avoid unwanted radiation, which might cause negative effects on the antenna's radiation performance. Measured results show identical operation characteristics for both polarization states. The common operating bandwidth between RHCP and LHCP states is from 2.44 to 2.47 GHz. The measured broadside gain is about 4.6 dBic. Compared with other related works, the proposed antenna can provide dual CP with the smallest number of pin diodes and the most compact dimensions.