Enhancement of the Focusing Properties of a Passive Radiometry Imaging System: A Theoretical Electromagnetic Study

A non-invasive imaging system, consisting of an ellipsoidal conductive cavity and radiometric receivers, designed and constructed in our laboratory the past few years is restudied. A means for further improvement of the ellipsoidal reflector´s focusing properties thus its performance is herein investigated. The main differentiating factor of our new approach is that the receiving antenna is more realistically modelled and also covered by two layers of different dielectric properties. The present paper provides details on the electromagnetic theoretical analysis of the problem and presents numerical results for the electric field distribution inside the head model, using two main operating frequencies, namely 0.5GHz and 1.5GHz for four distinct cases. The focusing optimization of the system in terms of spatial accuracy and penetration depth is assessed while the method and results are also separately validated.