Fast Analysis of Parallel-Plate Cylindrical Luneberg Lens Antennas Through Dyadic Green's Functions

An accurate analytic and computationally efficient method based on dyadic Green's function (DGF) is presented for the analysis of parallel-plate cylindrical Luneberg lens antennas. DGFs for electric and magnetic current sources are rigorously derived for an infinite parallel-plate waveguide filled with radially stratified media, which is the ideal model of cylindrical Luneberg lens antennas. The DGF for the electric current source is constituted of cylindrical vector wave functions and their associated coefficients, which is developed from the scattering superposition and the corresponding matching of boundary conditions, respectively. The DGF for the magnetic current source is proved to be directly related to the DGF for the electric current source by applying the second-kind vector Green's theorem. The proposed DGFs and the aperture field method are then applied to analyze the radiation characteristics of parallel-plate cylindrical Luneberg lens antennas with equivalent sources. Numerical results of several large-sized parallel-plate cylindrical Luneberg lens antennas show that the results of the proposed approach are in good agreement with those from commercial software simulations. The proposed approach has much less computational costs and can be used for the fast analysis of large-sized cylindrical Luneberg lens antennas.