Luneberg Lens as Passive Radar Augmenter for Aerial Target

Abstract

Aerial targets with required level of signature augmentation are used for artillery exercises. The Luneberg lens is a class of optical devices that finds potential applicability as passive radar augmenters for aerial target systems such as drones, tow-bodies etc. They effectively simulate dynamic target by providing mono-static radio frequency echo in the direction of radar required for the drills. The lens is a spherically symmetric structure and made of nonhomogenous dielectric material where refractive index (n) decreases radially from the center to the outer surface. It can produce radar cross-section that measures several hundred times that of a metallic sphere of same size. In practice, it is developed by layered assembly of discrete concentric shells, each of a different refractive index. A chosen portion of its outer surface is masked with a thin conductive layer for reflection. A comprehensive study has been carried out to configure, simulate and evaluate the performance of a compact Luneberg lens and have been discussed. Further, to achieve required detectability of an indigenous aerial tow-target system with specific RCS coverage, multiple lenses placed in different orientations have been configured and reported.