Development and Testing of the Time-Domain Microwave Nondestructive Evaluation System

There has been a continuing pursuit in developing an ultra-wideband (UWB) time-domain microwave impulse radar nondestructive evaluation (NDE) system at the University of Ilinois at Urbana-Champaign [1]. The UWB time-domain microwave NDE system employs a low power and UWB monocycle pulse source [1]. The advantages of the UWB time-domain system are its better spatial resolution, more information of the test targets, and shorter measurement time. However, the time-domain system suffers a worse signal-to-noise ratio (SNR) compared to the frequency-domain system. In order to improve the SNR of the time-domain system, the averaging (stacking), time-gating, and wavelets techniques [8,9] can be applied to the measurement data