Dual-band dual polarised printed antenna element

A novel printed antenna element capable of providing dual polarised operation over two widely separated frequency bands is described. The element consists of a perforated proximity-fed microstrip patch antenna operating at the lower frequency, layered over a subarray of aperture coupled microstrip elements operating at the upper frequency. Results for a specific example operating at L and X bands (a frequency ratio of 8:1) are presented. The impedance bandwidth for both bands is > 6%. with isolation within bands > 20dB and isolation between bands > 40dB. The element and feed network also has the advantage of being compact enough to be used in arrays, providing dual polarised dual-band operation from a single low-profile aperture.