A wide-band dual-polarization patch antenna for mobile applications

A broadband dual-polarization patch antenna fed by L-shaped probes at the patch corners is presented. A coupled line directional coupler mounted at the back of the ground plane is used to enhance the isolation between the L-probes to a large extent. Through using the coupler to feed the L-probes, the isolation between the input ports is 34 dB over the GSM900 operating bandwidth, which is enhanced by 14 dB. By using two plastic spacers to support the patch in the air, an impedance bandwidth of 18%, and an average gain of 7 dBi can be obtained for both ports. The far field patterns are stable across the passband. This antenna can potentially be used as a GSM900 base station antenna.