Dual-polarization and dual-frequency microstrip array antenna with high isolation

A new type of dual-polarization and dual-frequency multilayer-stacked microstrip array antenna is introduced. The feeding mechanism of the element is the aperture coupling for one polarization and the direct feeding for the orthogonal polarization. The microstrip element exhibits a wideband of operation. A slot etched on driven patch is used to improve isolation performance of the proposed antenna element, and the better impedance characteristic is obtained as well. Measured results agree well with the simulation, exhibiting a |S₁₁|≤10dB bandwidth of 16.6% in V-port and 14.28% in H-port. The measured isolation is better than 30dB. Good radiation patterns and low cross-polarization level are also confirmed.