A Wideband Circularly Polarized Filtering Antenna Based on Stacked Patch Structure

A circularly polarized (CP) filtering antenna design for wideband use is suggested. In this design, a four-layer microstrip antenna structure is proposed, which is consisted of the top square patch, square corner-cut patch, slot patch, and bottom reflector. Among them, the slot patch not only realizes the coupling feeding of the stacked structure, but also improves the CP performance. The radiation nulls are generated by shorting pin and slot patch, respectively. The suggested antenna may provide 67.15% (3.6-7.24 GHz) impedance bandwidth (IBW), 34.02% (4.83-6.81 GHz) axial ratio (AR) bandwidth, and about 8.65 dBi realized gain, according to simulation outcomes.