MINIATURIZED SINGLE-FEED CROSS-APERTURE COUPLED CIRCULARLY POLARIZED MICROSTRIP PATCH ANTENNA

A novel miniaturized single-feed cross-aperture coupled circularly polarized (CP) microstrip patch antenna loaded by four identical shorting strips is proposed and discussed. Each shorting strip underneath the edges of the radiating patch is connected to the ground plane via an array of three identical and equidistant shorting pins. With the assistance of the capacitance offered by the radiating patch and the shorting strips, and the inductance induced by the shorting pins, the patch size and overall size of the proposed antenna have been significantly reduced by 75% and 69%, respectively, compared with the conventional antenna. An antenna prototype with an overall size of 50 mm× 50 mm× 7.548 mm (0.317λ0 × 0.317λ0 × 0.048λ0) and a patch size of 29.43 mm × 27.85 mm (0.186λ0 × 0.176λ0) has been fabricated and measured, which shows a measured 10-dB return loss bandwidth of 92 MHz (4.76%) from 1.886 to 1.978 GHz with a maximum right-handed CP (RHCP) gain of 4.9 dBic. The measured 3-dB axial ratio (AR) bandwidth is 28 MHz (1.46%) from 1.899 to 1.927 GHz with a 3-dB AR beamwidth of more than 140 ◦ across the operating bandwidth.