Planar square and diamond microstrip patch array antennas for dual-polarization operation

Two compact low-cost planar microstrip array antennas devised to achieve dual-polarization capability are presented. The arrays are composed of five square patches with a central aperture-coupled element feeding the outer patches through a straightforward network of resonant microstrip lines. Dual-edge and dual-corner feeding arrangements for the external patches are considered as alternatives. By appropriately driving the two antennas at their input ports, dual-linear as well as circular polarization of the radiated field can be accomplished. Preliminary numerical investigations of the proposed antenna configurations are reported and the relevant performance is comparatively assessed.