A reconfigurable UWB system for real-time through wall imaging applications

A reconfigurable ultra-wideband system for through wall imaging application has been developed. The radar operating frequency can be selected to cover either 2-4 GHz or 8-10 GHz UWB bands. The lower UWB band is used to minimize through wall attenuation for relatively high loss wall materials, but the upper band can be utilized to achieve high image resolution for relatively low loss walls. A synthetic aperture radar has been developed that utilizes a wideband tapered slot Vivaldi array and covers an ultra wide frequency range, extending over 2-10 GHz; thus covering both regions. The developed beam-forming algorithm is based on near field models, and accounts for wall effects. Both the wave refraction and propagation speed changes are taken into considerations to obtain accurate images of various targets. Real-time experiments have been performed through both dry-walls and brick-walls to validate the performance of the radar system.

I. Introduction

The operation frequency is important for the optimal design and implementation of the see through wall imaging system. An 8–10 GHz operation has been utilized in [1] for penetrating drywall to get the best imaging resolution, but a 2–4 GHz has been recommended as the optimal frequency band for see through brick/concrete wall applications in [2] to minimize the through wall losses.