A Dual-Feed L-Probe Circularly Polarized Patch Antenna with Low Profile

A circularly polarized (CP) unidirectional patch antenna with low profile is presented in this paper. The antenna is fed by two symmetrical deformed L-probes connecting to a 180 degree phase-shifted Wilkinson power divider. A single-layer patch with a 45-degree tilted H-slot is used to realize circularly polarized. In particular, by adding four conductive walls around the antenna as rim edges to form a single square cavity, the axial ratio bandwidth is broadened and the profile is lowered. Simulated and measured results show that the antenna has a common 3-dB axial ratio bandwidth and 10-dB impedance bandwidth of 6.8% (from 1.43GHz to 1.54GHz) with the profile height of 0.059 λ0. In the operating band, the proposed antenna exhibits good wide-side CP radiation with a symmetrical radiation pattern and a high gain of more than 7.5dBic.