Research And Applications Of Targets’Electromagnetic Modeling For FDTD Method

In this thesis, aiming at the precision and validity of modeling problem in the calculation ofobjects’ electromagnetic scattering using Finite Difference Time Domain (FDTD) method, it putforward two kinds of modeling method based on commercial software. These two modeling methodsset up a3D model of the object using commercial CAD software (AutoCAD or CATIA), adopted acertain grid subdivision algorithm to discrete the model according FDTD calculation requirement,generated the corresponding geometrical–electromagnetic parameters description file. At the sametime, it studied the model reconstruction program and the interface between the description file andFDTD calculation program, which realized the approach of modeling accurately and effectively. Itsolved the obstacles of FDTD grid generation and the connection between the FDTD calculationprogram and modeling program effectively. This thesis is summarized as follows:(1) The FDTD difference iterative equations and its key technology are discussed. The FDTDgrid subdivision technology and modeling method are summarized comprehensively.(2) Electromagnetic modeling method for FDTD based on CAD software is studied. It solvedthe electromagnetic modeling problem of FDTD method using AutoCAD VBA secondarydevelopment. The grid discretion algorithm and FDTD electromagnetic modeling process is discussed;model reconstruction method is given to check the correctness of the algorithm; the interface betweendiscrete grid files and FDTD calculation program is designed. Finally some examples are given toverify the correctness and effectiveness of the modeling method.(3) Electromagnetic modeling method for FDTD using CATIA-GiD software is studied. Themodel is established in CATIA and imported to GiD to make grid subdivision. The multilayeredmedium model’s mesh subdivision is realized by properties addition. According to the characteristicwhich GiD can be divided to triangle surface model, the method is designed to generate conformalgrid based on triangle surface model. Several model calculation examples are given to demonstratethe correctness of the proposed method. In view of the difficulty of traditional modeling to achievemodeling of complex object accurately, this thesis gives examples of complex targets to demonstratethe effectiveness and superiority of the proposed modeling method.