A broad-band dual-polarized microstrip patch antenna with aperture coupling

In this communication, a dual-polarized aperture-coupled microstrip patch antenna with a broad-bandwidth high-isolation low cross-polarization levels, and lowbackward radiation levels is designed and its features are presented. For broad bandwidth and easy integration with active circuits, it uses the aperture-coupled stacked patches. The corner feeding of square microstrip patches is applied and the coupling aperture is the H-shaped aperture. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. A dual-polarized antenna is designed, fabricated, and measured. The measured return loss exhibits an impedance bandwidth of over 24.4% and the isolation is better than 30 dB over the bandwidth. 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. Both theoretical and experimental results for S parameters and radiation patterns are presented and discussed.