Analysis of Spherical Lens Antennas - Comparison of Three Analysis Methods

The paper presents a comparison of three approaches for analyzing spherical lens antennas - spectral-domain method, ray-tracing method, and time- domain finite integration technique (FIT) implemented in commercial software CST Microwave Studio^reg. The spectral-domain method takes advantage of transforming the three-dimensional problem into a set of one- dimensional problems. The spherical lens antenna is rigorously taken into account by implementing the Green's functions for the multilayer spherical structures. The ray- tracing method is a general analysis method that can be applied to all kinds of lenses with general (non-symmetric) shape. Finally, FIT implemented in commercial software is general purpose full-wave method. The results of the analysis are compared with measured radiation pattern of a 12 layer Luneburg lens antenna.