Ultra Wide Band Imaging Of Dielectric In The Time Domain Using Sensitivity Coefficient Based Reconstruction

M. Z. Abdullah1,3, W. Yin1, M. Bilal1, D. W. Armitage1, R. Mackin2 and A. J. Peyton1

1School of Electrical and Electronic Engineering, University of Manchester, Manchester M60 1QD, UK

2Department of Engineering, Lancaster University, Lancaster, LA1 4YW, UK

3 School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Penang, 14300, Malaysia Email: mza@usm.my

ABSTRACT

Ultra wideband (UWB) electromagnetic tomography (EMT) reconstructs the spatial distribution of the EM properties of the media based on the information such as the attenuation and delay of short EM pulses travelling through the imaging space. The forward problem in UWB EMT is to determine parameters, such as the wave arrival time and the attenuation of EM pulses for a media of given EM property distribution. The inverse solution is to reconstruct the EM property distribution in the imaging space. In this paper, the finite difference time domain (FDTD) method is used to solve the forward problem from which the system sensitivity maps are determined. Image reconstruction is based on inversion of the sensitivity matrix. Experimental data from a laboratory UWB system with high contrast targets in an aqueous media. The results show that this technique can accurately detect and locate unknown targets in spite of the presence of significant levels of noise in the data.

Keywords Ultra wideband, electromagnetic tomography, wavelet transform, FDTD, Inverse solution.