Design and analysis of a spatially selective mirror for sub-millimeter wave imaging

摘要

In this paper a two dimensional electromagnetic analysis and numerical simulations for a structure consisting of a resistive sheet backed by a spatially non-uniform perfectly conducting reflector is presented. The analyzed non-uniformity is a dip or bump on the reflector surface. The analysis is aimed at the design and evaluation of this structure as a spatially selective mirror for use in a single pixel sub-millimeter wave imager. Scattered and absorbed powers as well as the scattered radiation intensity are calculated in the far field for illumination by a linearly polarized, tapered Gaussian beam. Simulations for normally incident radiation and radiation at obtuse angles are presented. The scattered field in the far region is measured (simulation) by a receiving antenna and the dependence of the simulated received power on the position of the non-uniformity is observed. The dependence of the simulated received power on the size of the non-uniformity on the reflector is also presented. We conclude with the description of a single pixel sub-millimeter wave imager that uses the analyzed structure.