Passive Microwave Non-Destructive Testing System Based on Back-Scattering Sensor

This paper proposes a non-destructive testing (NDT) system for composite materials, basing on a back-scattering passive wireless microwave sensor. The back-scattering sensor is designed to generate nine resonances within 4-7.5GHz. The performance of the system is demonstrated using by both simulation and experiment. From the simulated and experimental results, the proposed NDT system is used to locate the defects of composite materials, where the offset of the resonant frequency of the sensor follows the position of the defects. With the low-profile and print-ability of the sensor, this work paves the way for defect sensing and monitoring on composite material structures.