Bulk material dielectric property measurement by an adapted free-space UWB inverse scattering method

This paper presents a system to measure the bulk dielectric properties of a non-metallic target. It is intended as a first step towards a multi-antenna pixel type, imaging system using the same principles. The system, based on the free-space method, comprises two Ultra-Wide Band (UWB) antennas sub-merged in a tank of lossy background liquid. Data is collected by submerging the Object Under Test (OUT) between the antennas and performing a transmission measurement. The dielectric properties of the OUT are recovered using a UWB inverse scattering algorithm. This employs a 3D Electro-Magnetic (EM) simulation of the system that uses a static conductivity material model. The system is calibrated by means of a measurement without the OUT present. Dielectric properties of a range of materials are recovered to within 10 % of the ground truth. Results suggest that a pixel based imaging system may be viable.