Analysis of spherical lens antennas - comparison of two approaches

The paper presents a comparison of two approaches for analyzing spherical lens antennas - spectral-domain method and ray-tracing method. 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. Different types of feeding antennas can be easily included in the analysis method by calculating the vector-Legendre transformation of the equivalent or physical currents that represent the considered feed. The ray-tracing method is a general analysis method that can be applied to all kinds of lenses with general (non-symmetric) shape. The results of the analysis are compared with measured radiation pattern of a 12 layer Luneburg lens antenna.