Bandwidth and polarization characteristics of perforated patch antennas

Perforated microstrip patch antennas were investigated as candidates for elements of large dual-band dual-polarized arrays. Perforations allow the incorporation of the small patches of the high frequency bands to be placed within the perforated patches of the lower frequency band array, allowing one to maintain a symmetric array lattice dictated by the scan range and grating lobe locations. It was found that perforations cause rapid changes of current directions, making numerical optimization more difficult and causing high cross polarizations. Dual-balanced feed configurations were utilized to ensure low cross polarizations. To enhance the bandwidth, both stacked patches and raised elements were investigated. They provided similar bandwidths and cross polarizations. However, the stacked patch configuration resulted in a more compact size and smaller over all height. The raised element, on the other hand, provided higher gain