Reflectarray probe optimization at millimeter frequencies

Abstract

The near field of a reflectarray at 100GHz is optimized in order to increase the size of the quiet zone for its use in compact antenna test ranges. In order to compute the radiated near field, a simple model of the reflectarray is used in which the field is obtained as contributions of the far field radiated by each unit cell, modeled as a small aperture by means of the second principle of equivalence. Then, the Levenberg-Marquardt algorithm is employed to optimize both amplitude and phase in order to maximize the size of the quiet zone in different planes. From the obtained phase distribution, a design is carried out. Simulations are compared for the near field before and after the optimization, showing an important improvement of the size of the quiet zone in the main cuts of the near field.