Experimental Study on Permittivity Estimation Method for UWB Internal Imaging Radar

Ultra-wideband (UWB) radar, with high range resolution and ability of penetrating dielectric media, has a great potential for innovative non-destructive testing for aging roads or bridges or non-invasive medical imaging. We have already proposed an accurate permittivity estimation method for a homogeneous dielectric object based on the geometrical optics (GO) approximation, where dielectric boundary points and their normal vectors are directly reproduced by the range point migration (RPM) method. In addition, the finite-difference time domain (FDTD) based waveform reconstruction method was incorporated to compensate for errors incurred by the GO approximation. This paper shows the experimental investigation of this method, where the new approach for suppressing the creeping wave along dielectric boundary is introduced. The results from real observation data validate its effectiveness, in terms of highly accurate permittivity estimation and buried object boundary reconstruction.