Fourier–Bessel Basis Functions for the Analysis of Elliptical Domain Metasurface Antennas

An approach based on the method of moments and using a set of stretched Fourier-Bessel basis functions (FBBFs) is presented for the analysis of elliptical domain metasurfaces (MTSs). This shape is preferred to the traditional circular domain, when a better control of the aperture efficiency is required. The proposed formulation makes use of a harmonic decomposition of the substrate dyadic Green's function to efficiently compute the reaction integrals. It is shown that the computation time associated with the sheet impedance matrix calculation is almost not affected by the stretching of the FBBFs. The obtained formulation is efficient since the orthogonality of the FBBFs is preserved and well adapted to an MTS optimization process. The simulation results are compared with measurements of a realistic MTS antenna implemented with subwavelength printed patches.