Dual-Polarized Multilayer L-Band Asymmetric Subarray with Truncated Electric Walls Separation for Airborne SAR Applications

A novel planar phased array of 5x4 multilayer dual polarized aperture coupled stacked patch elements, operating in L-band, with beam steering in elevation and excited with an asymmetric amplitude distribution in azimuth, is presented in this work. The proposed design exploits the restricted available antenna size (2.45 lambda(0) x 1.97 lambda(0)) maximizing the number of array elements by means of an interelement spacing of 0.48 lambda(0) and the use of truncated walls. The measurements of the manufactured prototype show an antenna bandwidth of almost 20%, polarization isolation greater than 23 dB and directivity values above 15 dB. Despite the close proximity among the array elements, the measured coupling levels between the feeding ports are lower than -20 dB for the center frequency of operation 1.325 GHz, which makes the proposed work suitable for airborne Synthetic Aperture Radar systems, where a high degree of integration is required.