Design considerations for dual polarized aperture-coupled microstrip patch antennas

The paper discusses the design of aperture-coupled microstrip patch antennas for dual linear polarization with special emphasis on achieving a wide bandwidth and a high polarization isolation. The coupling behavior of crossed slot and offset slot designs are discussed and compared to each other. Several design examples for aperture-coupled antenna elements illustrate how the polarization isolation decreases as the bandwidth of the antenna elements is increased. A feeding concept for an 8/spl times/1 element subarray yielding a polarization isolation of larger than 45 dB is presented.