Design of an Annular Slot Loaded Circularly Polarized Reconfigurable Antenna

In this study, we present a unique and innovative design for a reconfigurable patch antenna with circular polarization. The antenna configuration we propose features a square patch with two square slots placed vertically and four annular slots positioned at each corner. By regulating the operating conditions of the four diodes integrated into the antenna, a seamless shift from right-hand circular polarization to left-hand circular polarization, and vice versa, can be effectively attained. Through extensive simulations conducted using the CST Simulator platform, it has been observed that the reconfigurable antenna offers a substantial operational bandwidth in both states of polarization. The antenna exhibits an impedance bandwidth (S$_{11} \lt -$10dB) of 8.68% (13.16 GHz to 14.35 GHz) and a 2.33% bandwidth (13.55 GHz to 13.87 GHz) for axial ratio, with a 3 dB threshold. Furthermore, the designed antenna achieves a maximum gain of 6.7dBi along the bore sight direction. Its compact form, high gain over a wide frequency spectrum, and the ability to reconfigure make it highly suitable for Ku band utilization.