Fast Sweep Frequency Calculation Method Of Microwave Circuit And Scattering Characteristics

In microwave circuit design,the finite element numerical simulation algorithm of computational electromagnetics plays an extremely important role.The first step of finite element numerical simulation is to model and discretize the simulated device.Considering the requirement of accuracy,it is bound to encrypt and subdivide to build a large-scale finite element system.In addition,in the analysis and design of microwave circuits,the electromagnetic response over a wide frequency band is an area of great concern to engineers.Solving such a large-scale system on a wide frequency band by frequency point is a huge challenge for the performance,memory and algorithm efficiency of the computer.With the complexity of microwave device structure and the increase in electrical size,it is very important to research or improve an efficient numerical algorithm.Based on the above starting points,the main research works of this thesis are as follows:Firstly,this thesis introduces the basic principle of the finite element method(FEM)and describes the steps of the FEM to solve the boundary value problem of electromagnetic field in detail.On the basis of the FEM,this thesis introduces the model order reduction(MOR)of FEM based on SOAR(Second-order Arnoldi)algorithm,explains its reduction principle and the advantages of reduced-order frequency sweep,and introduces the process of MOR.Then,in view of the fact that the traditional MOR will solve a system with the same scale as the original finite element system multiple times during the order reduction process,the thesis tries to use domain decomposition technology to improve the performance of the traditional MOR.This method takes advantage of the characteristic of domain decomposition method(DDM)that can transform the solution of large-scale finite element systems into solutions of several small systems,so as to achieve the purpose of "dividing and conquering" to the reduction of a large-scale complex model.This thesis introduces the basic theory of DDM in detail,and the principle of boundary value transfer between sub-domains.This thesis develops a new MOR based on the DDM technology,which greatly reduces the memory consumption and improves the computing efficiency.Finally,this thesis studies the use of MOR to analyze the electromagnetic scattering characteristics of metal objects.This thesis introduces the basic theory of FEM analysis to electromagnetic scattering and the method of solving RCS(Radar Cross Section)in detail.Solving the broadband RCS needs to solve the finite element matrix of each frequency point,which issimilar to the original intention of using MOR to sweep the frequency.This thesis studies and develops a method which can solve the target broadband RCS based on MOR,and using this method to calculate the RCS of multiple metal targets,verify the correctness and efficiency of the algorithm.