Design and analysis of a novel wideband microstrip antenna

Theoretical and experimental results of a novel wideband planar antenna are presented in this paper. This antenna can achieve a wide bandwidth, low cross-polarization levels and low backward radiation levels. For wide bandwidth and easy integration with active circuits, it uses aperture-coupled stacked square patches. The coupling aperture is an H-shaped aperture. Based on the finite-difference time-domain method, a parametric study on the input impedance of the antenna is presented, and effects of each parameter on the antenna impedance are illustrated. One antenna is also designed, fabricated and measured. The measured return loss exhibits an impedance bandwidth of 21.7%. The cross-polarization levels in both E and H planes are better than -23 dB. The front-to-back ratio of the antenna radiation pattern is better than 22 dB.