Capacitively Coupled Single-Layer Dual-Band Circularly Polarized GPS Ring Antennas

A low profile, capacitively coupled circularly polarized dual-band Global Positioning System (GPS) antenna with orthogonal dual feed is simulated and presented. The antenna is designed to operate at the GPS L1 (1575.42 MHz) and L2 (1227.60 MHz) frequencies. Geometric parameters are varied to test the effect on the operating frequencies, axial ratio, and radiation pattern. A bandwidth of 7 MHz at L1 and 5 MHz at L2 was achieved. The 3 dB axial ratio beamwidth was 72° at L1 and 180° at L2. These results were achieved with overall patch dimensions of 55.6mm X 55.6mm on a single layer.