Time-domain ultra-wideband imaging radar experiment for verifying super-resolution in nonlinear inverse scattering

This paper presents an experimental verification of the super-resolution phenomenon in nonlinear inverse scattering using a time-domain (TD) ultra-wideband (UWB) imaging radar system developed at the University of Illinois at Urbana-Champaign. The TD-UWB microwave imaging radar system successfully combines the UWB impulse radar system and a nonlinear inverse scattering imaging algorithm, the distorted-Born iterative method (DBIM), for nondestructive evaluation (NDE) and remote sensing purposes. The experimental data were collected from a limited view angles using a switched Vivaldi antenna array which consists of five transmitters and six receivers. The experimental data are processed with the DBIM, and show that it can resolve features smaller than the half-wavelength dictated by the Rayleigh criterion. The experimental results also demonstrate that DBIM can recover information on the backside of a penetrable scatterer even though scattering data are collected only from limited view angles from the front side of the scatterer.