Computation of Input Impedance of Rectangular Waveguide-backed Metasurface Arrays with Feed Networks using Coupled Dipole Framework

We present a method for computing the input impedance of a rectangular waveguide-backed metasurface array excited by a common feed network. The metasurface array consists of rectangular waveguides loaded with subwavelength metamaterial radiators fed by the guided modes, excited with the feed. Thus, computation of the impedance at the input feed requires considering the electromagnetic interaction of the metasurfaces with its feed. Recently, semi-analytical models of metasurfaces using a coupled dipole framework have been proposed as efficient analysis tools. However, the models assume ideal waveguide ports for excitation and do not incorporate the response of feed networks, thus creating a gap in analyzing the overall response of the antenna. This paper addresses this gap by presenting a method using the coupled dipole framework and segmentation technique, which utilizes the impedance matrices for cascading multiport networks representing the metasurfaces and feed. The proposed method is verified via full-wave simulations.