Analysis of Spherical Lens Antennas using Spectral Domain Approach

The paper presents the method for analyzing spherical lens antennas. The method takes advantage of the spectral-domain approach by which the three-dimensional problem is transformed 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. A number of numerical techniques are applied in order to enable the analysis of electrically large lenses. The results of the analysis are compared with measured radiation pattern of a 12 layer Luneburg lens antenna.