Broadband Circularly Polarized Combinatorial Slot Antenna

Abstract

A broadband circularly polarized (CP) combinatorial slot antenna is proposed. Irregular slot combined with rectangles and semicircles is adopted to achieve both broadband and circularly polarized characteristics. Meanwhile, an accessorial slot is cut at proper position to broaden the bandwidth. A simple 50Ω microstrip line is used to excite this combinatorial slot. The proposed antenna has a small size of 40 × 40 × 1.5 mm3, and the 3 dB axial ratio bandwidth is 1.45 GHz (2.8–4.25 GHz) and 0.25GHz (5.15–5.4 GHz), which are 41.1% and 4.7% respectively. The peak gain of the antenna is 3.5 dB which appears at 5.5 GHz.