Microwave Nondestructive Defect Identification Using Sensitivity Analysis

We propose a novel near-field approach to microwave non-destructive detection and evaluation of defects. The problem is expressed as an inverse least square problem solved using a gradient-based optimizer. The required response gradient is obtained with an adjoint-based sensitivity analysis technique developed here to handle materials with complex permittivity. It allows the recovery of the shape and the material parameters of the defect. The …