Field Transformation Approach to Designing Lenses

Abstract

This chapter presents a technique--referred to herein as the Field Transformation method--for designing flat lenses, as well as flat-base Luneburg lens antennas for wide-angle scanning using waveguide array feeds. The performance characteristics of these lenses are compared with those based on Transformation Optics (TO) paradigm, which has been recently developed as a tool for designing lenses of the same type. It is shown, via several examples, that the Field Transformation approach leads to designs which use conventional materials that are conveniently realizable, as opposed to metamaterials or those with anisotropic properties, that are often called for and are difficult to realize in TO-based designs. Furthermore, the Field Transformation approach enables one to control both the phase and amplitude distributions in the aperture of an antenna, which is difficult to do when employing the geometry transformation approach prescribed in the TO paradigm.