Microwave Transmission-Line Lens Matched with Free Space

Abstract

In order to mitigate the problem of unwanted reflections from a homogeneous dielectric lens, a lens based on periodic networks of transmission lines is proposed. Since the propagation constant and the impedance of the network can be varied to a large extent independently from each other, it is possible to realize a lens with a high index of refraction while having almost perfect impedance matching with the surrounding medium.