Lens Antennas

Abstract

Lenses can be employed to act as high‐gain scannable antennas. The optical principles that apply to lens antennas are discussed, as well as the materials used in the construction of lenses. The basic lens function is discussed, and examples given of simple planoconvex and planoconcave lenses, together with the equations that describe the lens surfaces. In order to reduce the lens size, lenses are zoned, and equations for lens zoning are given. Other lens parameters such as gain, sidelobe level, reflections, loss, and bandwidth are treated. Lens systems for scannable or multibeam antennas are described, and design and analysis procedures for Rotman lenses given. Other lenses discussed include Luneburg, R ‐2 R , integrated dielectric, and Fresnel zone lenses. Physical construction methods for Rotman, Luneburg, and Fresnel zone plate lenses are discussed. This includes three‐dimensional (3D) printing and use of metamaterials.