Hybrid Circular Ground Planes for High-Realized-Gain Low-Profile Loop Antennas

A novel hybrid circular ground plane integrated with a loop antenna is presented. The ground plane is composed of two different rings: a ring with periodic gaps and an annular concentric ring. The combination of the two rings into one ground plane improves significantly the radiation performance of the radiating element. The proposed antenna is designed to resonate at 2.9 GHz with a return loss of -\text{24} dB and a realized gain of 10.5 dB. To experimentally verify the simulated results, a prototype was fabricated and measured. The simulations and the measurements are in excellent agreement.