Polarization Reconfigurable Circular Patch Antenna With a C-Shaped

Abstract

Polarization reconfigurable circular patch antenna with a C-shaped slot is proposed in this paper. It is demonstrated that by introducing a reconfigurable C-shaped slot in a circular patch antenna, the polarization of the radiation of the antenna, operating either in a linearly or circularly polarized mode, can be switched effectively. It is switched between vertical and horizontal polarizations for a linearly polarized mode and switched between left hand circularly polarization (LHCP) and right hand circularly polarization (RHCP) for a circularly polarized mode. The polarization reconfigurable characteristic is realized by controlling the states of the two switching diodes mounted over a concentric circular slot incorporated on the patch, so as to vary the orientation of the C-slot. Prototypes of both linear polarization (LP) and circular polarization (CP) designs were developed and the performances were validated against measurements. Both antennas exhibit over 20% impedance bandwidth (SWR<2) and perform broadside radiation over the operating band. The 3-dB axial ratio bandwidth for the circularly polarized case is 4%.