Design of mmW Broad-Beam Reflecting Surface Using Grey Wolf Optimizer

In this paper, a 28-GHz broad-beam planar reflecting surface (RS) is developed by optimizing the reflection phase distribution through the gray wolf optimizer (GWO) algorithm. The pattern mask is carefully determined for the cost function to achieve a satisfactory result. Specifically, the reflection phase distribution of RS composed of $35 \times 35$ unit cells with the 3-dB beamwidth of 30° is acquired. By applying the phase distribution to the RS, the calculation and full-wave simulated results in terms of normalized array patterns show good agreement, thus validating the adopted approach.