Polarization Agile Circular Polarized Crossed Dipole Antenna For Sub-6 GHz Band

A circular polarized crossed-dipole antenna (CPDA) with reconfigurable polarization is presented. To generate circular polarization, two dipole antennas are placed orthogonally, and fed by quarter-vacant rings that produce 90° phase delay. PIN diodes are inserted in between CPDA and quarter-vacant rings for polarization switching. Either left-hand circular polarization (LHCP) or right-hand circular polarization (RHCP) can be selected by applying bias voltage to the diodes. To validate LHCP/RHCP switching and far-fields characteristics, the proposed CPDA is fabricated and measured. Experimental results show that the antenna has fractional impedance bandwidth covering 3-dB AR of 8.8% (3.57-3.9 GHz). Measured peak gain of the antenna has maximum gain of 5.9 dBiC at 3.5 GHz.