A Current-Based Algorithm for the Design of Metasurface Antennas

This paper proposes an algorithm for the automated design of metasurface antennas. From the objective radiation field and the feeding structure, it allows to obtain a surface current distribution that leads to a passive and lossless impedance profile on the radiating aperture. The surface is modelled by a scalar impedance boundary condition and the electromagnetic problem is formulated as an electric field integral equation. The approach is entirely numerical, based on the gradient descent optimization of a scalar objective function that incorporates passivity and far field requirements. This procedure was applied to the design of an electrically large circular metasurface antenna at 32 GHz, obtaining a lossless impedance profile with satisfactory radiation properties.