Review of imaging architecture

Abstract

This paper reviews various passive mm-wave imaging systems. It includes sources of radiation, atmospheric transmission and a brief summary of their various applications. This is followed by a review of methods for detecting mm-wave radiation. From a cost analysis it is shown that scanned systems are at present far more cost effective than focal plane array of receivers for high performance systems. There is a review of the various types of imaging system available with greater emphasis being placed on recent developments and their methods of beam forming. It is concluded that at present, and for the foreseeable future, optical beam forming and beam steering are the most cost effective. Some general remarks are included as to how receivers are matched to their collection apertures, followed by a section on optical beam forming components. The recent development of a lightweight, low cost, high performance reflective lens is included. It is then shown how this may be combined with mechanical scanning systems to form high performance passive mm-wave imaging systems.