A Double Layer Circularly Polarized Filtering Antenna with Parasitic Patches

Abstract

Without any extra filtering structure, a double layer circularly polarized (CP) filtering antenna with parasitic patches is proposed. The truncated-corner square patch and the microstrip feeding line are the two sets of parasitic patches that make up the bottom patches. For the purpose of enhancing CP performance and producing high-frequency band radiation null, the crossed slot is carved on the top patch. Radiation nulls for the upper and lower stopbands are provided, respectively, by two sets of parasitic patches at the bottom patch. The measured findings show that the suggested antenna may provide a peak realized gain of about 7.07 dBi and an impedance bandwidth (IBW) of 17.72% (2.16-2.58 GHz) and 9.32% (2.25-2.47 GHz) axial ratio (AR) bandwidth.