Planar wide-scan wideband phased arrays with improved polarization purity
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Abstract
One of the common requirements for wideband wide-scanning arrays in multifunctional platforms is the polarization agility. Cross-polarization levels should be kept low within the entire field of view and frequency band of operation. However, good polarization purity is hard to achieve especially for arrays that are designed to operate over multi-octave bandwidth. Planar wideband array often use dielectric slabs above the antenna aperture to improve the matching while scanning and increase the front-to-back ratio. However, dielectric superstrate deteriorate the polarization performance on the diagonal planes. The characteristic cross-polarization of a connected slot array in the presence of artificial dielectric layers superstrates is analyzed. An approach to reduce the cross-polarization is then investigated, consisting of localizing the artificial dielectric only in specific regions of the unit cell, rather than on the entire area. Index Terms–Artificial dielectric layers, connected arrays, cross-polarization, wideband arrays, wide-scanning arrays.