Broadband Circularly Polarized Patch Antenna With Parasitic Strips

A patch antenna with parasitic strips is presented for wideband circular polarization. In order to broaden the axial-ratio (AR) bandwidth of the original corner-truncated patch, four parasitic strips are sequentially rotated and gap-coupled around the patch. A capacitive-coupled feed with a small disc on the top of the feeding probe is utilized to obtain a wide impedance-matching bandwidth. Moreover, another disc-loaded shorting pin is placed at the center of the antenna to adjust the squint beams and improve the gains along +z-axis. Measured results show that the proposed antenna with a low profile of 0.13λ₀ obtains a global bandwidth of 24% (2.32-2.95 GHz) for |S₁₁| <; -10 dB, AR <; 3 dB, and average gain of 8 dBic.