Gain enhancement of circular patch antenna using parasitic ring

This paper investigates the performance of a circular patch antenna deployed with a parasitic ring and compares the performances with a conventional circular patch antenna in terms of gain, return loss, and radiation pattern. The antenna is fed by a coaxial probe and provided with a full ground plane. Compared with previous gain enhancement methods, the proposed metal ring resonator offers reduced design complexity. With a simple parametric study, the optimum width of the parasitic ring could be identified. Adopting this method, the proposed antenna has increased gain approximately 20% while maintaining the return loss at an operating frequency of 5.8 GHz.