Analysis of Scanning and Multi-Beam Antennas Based on Spherical Lenses with Array Feeds

This paper deals with the analysis of a spherical lens fed by an array of feed antennas. The spherical lens structure is accurately and efficiently analyzed by a spherical wave expansion method. The boundary element method is used for modeling of arbitrarily shaped feed antennas. Combining these two methods, a hybrid method is developed for accurate calculation of the input impedances and mutual coupling between the array elements, and the far-field radiation pattern. The main advantage of this approach is that all the electromagnetic interactions in the lens/array feed system are included in the analysis. Also, the feed antennas of complex shape may be accurately modeled while earlier developed methods, for the analysis of this type of antennas, are based on some assumptions for the feed current distribution. Comparing to commercial software packages, the hybrid method significantly reduces both computational time and memory requirements while providing high accuracy.