Reflectarray Antennas

Preface

High‐gain antennas are an essential part of long‐distance wireless communications, radar, and remote sensing systems, which vary with frequency, coverage, resolution, and flexibility of operation. The conventional choices for antennas in these systems were typically reflectors, lenses, or arrays. In recent years, however, a new generation of high‐gain antennas has emerged that combines the favorable features of both printed arrays and reflector antennas and creates a high‐gain antenna with low‐profile, low‐mass, and low‐cost features. This antenna is known as the reflectarray.

The reflectarray is an antenna with a flat reflecting surface consisting of hundreds of elements and an illuminating feed antenna. The hybrid nature of the reflectarray antenna offers more flexibility in aperture phase control and can provide advantages over both reflectors and array antennas for many applications. The elements of the reflectarray are individually designed to reflect the electromagnetic wave with a certain phase to compensate for the phase delay caused by the spatial feed. The phase shift of the elements is realized using various methods such as variable‐size elements. Single and multilayer reflectarrays have been designed to achieve broadband and multiband performance from microwave frequencies up to the THz range. Meanwhile, the direct control of the phase of every element in the array allows multi‐beam or shaped beam performance with single or multiple feeds. Another advantage ...