A Single-Layer Circularly Polarized Filtering Patch Antenna With Frequency Reconfiguration

A single-layer patch circular polarization antenna with filtering response and frequency reconfiguration is presented. The radiating patch is loaded with two notches and eight shorting pins. Two orthogonal modes are excited by a single coaxial probe feed. Four varactors are symmetrically loaded around the center of patch to achieve frequency tuning. Two radiation nulls are created for improving the band selectivity. For verification, a circularly polarized filtering antenna tuning from 2 GHz to 2.6 GHz is designed and simulated.