Efficient Method of Moments Analysis of Metasurface Antennas

This paper presents an efficient approach for the method of moments (MoM) analysis of metasurface (MTS) antennas. Instead of simulating the actual structure, made of several thousands of subwavelength patches, the presence of the MTS is accounted for using an impedance boundary condition in the integral equation. Then, when the MTS antenna exhibits rotational symmetry, the integral equation can be efficiently solved adopting a formulation for bodies of revolution. On the other hand, a novel type of basis functions can also be applied to the analysis of planar MTSs without any particular symmetry. The advantages of such basis, in both the space and spectral-domain, are outlined. Indeed, their closed-form spectrum allows one to efficiently compute the MoM impedance matrix using the spectral-domain approach. More importantly, these basis functions represent the global evolution of the surface current density in an effective manner. In both approaches, one obtains a drastic reduction in the number of unknowns, with respect to the cases in which the actual structure has been meshed with sub-entire domain basis.