A Wideband Polarization Reconfigurable Antenna With Partially Reflective Surface

A novel partially reflective surface (PRS) antenna is proposed, which can electronically alter its polarization between linear polarization, left-hand circular polarization (CP), and right-hand CP. The antenna consists of a shorted annular patch antenna as the source, a PRS structure to enhance the gain, and a reconfigurable Wilkinson power divider as the feed network. Four p-i-n diodes are inserted into each branch of the power divider to change its electrical length. By switching the p-i-n diodes ON and OFF, a phase difference of 0 degrees, 90 degrees, or -90 degrees can be realized at the two output ports of the feed network, hence enabling the antenna to radiate either a linearly polarized signal or left/right-handed circularly polarized signal. A prototype antenna with the biasing network is designed, fabricated, and measured. Good agreement between the simulated and measured results is achieved. Measurement results show that the proposed antenna has an overlapped 10-dB impedance bandwidth and 3-dB axial-ratio bandwidth of 4.7-5.36 GHz (13.1%). The average realized gains are similar to 9 dBi/dBic, which remain reasonably stable for different polarizations. The proposed antenna outperforms most of the reported polarization reconfigurable antennas for its wide bandwidth and relatively high gain.