An ultrawide-band microwave radar sensor for nondestructive evaluation of pavement subsurface

A new ultrawide-band (UWB) microwave radar sensor operating from 0.6 to 5.6 GHz has been developed using microwave integrated circuits for pavement subsurface characterization. UWB antennas operating from 0.5-10-GHz have been designed and tested for use in the sensor. A new simple, yet effective, accurate procedure was also developed to compensate for the common amplitude deviations and nonlinear phase errors produced by the inherent imperfection of the system. The developed compensation method is applicable to other systems and effectively reduces the potential masking of adjacent targets as well as facilitating and increasing the accuracy for target identification of the sensor. The sensor has been used to assess a pavement sample with less than 0.1 in of error in the pavement´s layer thickness. The developed system represents the first UWB stepped-frequency radar sensor completely realized using microwave integrated circuits over the frequency range of 0.6-5.6 GHz for subsurface sensing applications.