Development of a Plane Lens for a Tapered Anechoic Chamber

The study of the field formation in the quiet zone of a tapered anechoic chamber with a plane lens is considered. The operating frequency range of the tapered chamber is 0.1-1 GHz. The presence of a lens in this measurement facility provides the quiet zone with a diameter of 3 m. Previously, a hyperbolic lens 4 m in diameter with a matching layer around it on both sides has already been studied. The plane lens is considered as an alternative to the hyperbolic one. The plane lens should be made of a material with a variable dielectric permittivity. A specific example of the plane lens made of a composite material, namely inclusions of glass beads (quartz glass) inside the foam is considered. This lens can be made in a layered approximation, setting a constant value of the refractive index inside each layer. It is shown that such lens with a diameter of 4 m, consisting of seven layers with a constant permittivity of each layer, provides approximately the same field distribution non-uniformity in the quiet zone of the chamber as the hyperbolic lens studied earlier.