A High-Isolation Dual-Polarization Microstrip Patch Antenna With Quasi-Cross-Shaped Coupling Slot

A novel dual-polarization microstrip patch antenna fed by quasi-cross-shaped slot with high isolation (greater than 50 dB) over a wide bandwidth from 3 to 4 GHz is investigated. Four identical slots-referred to “quasi-cross slot”-are arranged symmetrically in an unconnected cross configuration in the center. The isolation between two orthogonal polarizations of the proposed antenna can be greatly improved over the conventional cross slot. A prototype was fabricated and measured. The maximum achievable gain of the proposed antenna is 9.6 dBi with a gain variation of 0.6 dBi over the bandwidth of 200 MHz (3.4-3.6 GHz). The design is suitable for array application in MIMO system. Details of the proposed design and experimental results are presented and discussed.