Microwave Imaging Algorithm Iterative Method Based On Spatial Domain

In electromagnetics, microwave nondestructive testing technology is the forefront of a very practical issue, and the core part is the microwave imaging algorithm. Microwave imaging algorithm is a microwave, electronic and digital image technology combining high-tech detection methods. Depending on the target object field where the scattering region the scattering information, technology to rebuild its internal structure is called the electromagnetic inverse scattering imaging technique.Based on electromagnetic scattering theory, we compare and study of several widely used numerical method for electromagnetic fields. We chose the finite element method to solve electromagnetic scattering problems. Based on the basic idea of finite element method, we use the high-frequency resonant state analysis module of ANSYS software to simulate the plane wave incident reinforced concrete imaging region with the scattering phenomenon, under different conditions to obtain the scattering information for follow-up imaging provides a useful positive to analyze the data.By the relatively mature imaging algorithm, we find that the inverse problem can be solved directly. Iterative method for solving spatial domain equation, the scattering region should be required a priori assumption. First, we assume that scattering properties for a specific region for next iteration. Then we calculate the Frechlet derivatives in order to solve different scattering region is the problem. Spatial domain iteration method has the advantage of more precise inversion of the scattering region. In this issue, we achieve high-frequency electromagnetic fields on the 3D finite element model for simulation analysis, using APDL language in ANSYS development program.Then we provide the necessary data for the imaging algorithm. Finally, we use these data, based on conjugate gradient method, using MATLAB image reinforced in different locations, indicating the location of reinforcement. Imaging results observed map in MATLAB, comparing the imaging position and the actual reinforcement location, it can clearly show the location, there is bias only the size of the horizontal section of imaging. Seen from the imaging results map in reinforced in two different locations, there is a small deviation between imaging position and actual position of media column, so the conjugate gradient method is feasible.