Mapping-Based Pattern Synthesis of Concentric Elliptical Arrays for Sidelode Suppression and Aperture Reduction

One of the ultimate targets of array pattern synthesis is to maintain the mainbeam while suppressing the peak sidelode level (PSLL) within a smaller aperture size. The mainbeam gain proportionally increases with the aperture size, whereas the PSLL is uncorrelated approximately. This regular is useful for adjusting the array pattern as changing the aperture size. However, when the mutual coupling effect among the coupled array elements is considered, for some kinds of nonuniform arrays, e.g., the concentric ring array or the concentric elliptical array (CEA), the PSLL property would change significantly when the same array arrangement with different aperture sizes is used. On the purpose of both the PSLL suppression and the aperture reduction, this letter presents a pattern synthesis approach of real coupled CEAs. The form of elliptic ring is mainly introduced for the aperture reduction, and the ellipse-axis ratio, together with the ring radii and the position of each array element along the elliptic rings, are optimized simultaneously for the PSLL suppression. Typical examples are provided to validate the effectiveness of the synthesis approach. This approach also gives an alternative way for the adjustment of real coupled arrays after the theoretical synthesis.