Simple-Structured Dual-Slot Broadband Circularly Polarized Antenna

A simple-structured single-fed dual-slot broadband antenna with circularly polarized waves is presented. Two semicircular slots etched in the ground plane were used as the radiators. The slots were proximity-coupled to a 50 Ω microstrip feedline printed on the other side of the substrate. The fabricated antenna with an overall size of 101 × 64 × 1.52 mm
³
yielded a very wide –10 dB impedance bandwidth of 86.9% (3.63–9.21 GHz) and a 3 dB axial-ratio bandwidth of 74.3% (4.18–9.12 GHz). The measured antenna peak gain in the broadside direction over the axial-ratio bandwidth ranged from 3.9 to 7.3 dB. Good agreement between the simulated and measured results validates the proposed antenna.