Electromagnetic Fast Analysis For Finite Periodic Structures

The finite-period structure is an array structure consisting of unit scatterer arranged periodically,and has become a widely used artificial electromagnetic material.It is often used in the field of antenna,RF lines and frequency selectivity.Therefore,analyzing the electromagnetic scattering of finite-period structures has long-term significance for its engineering applications,and the key point and difficulty is to reduce the amount of calculation and storage in the calculation process.After the introduction of Method of Moments(MoM)into the field of electromagnetism,it has always been one of the most important methods in the field,and it plays an important role in calculating the electromagnetic problem of medium-sized target.However,in the process of calculating electromagnetic scattering of finite-period structures by using this method,as the number of unit increases,the amount of calculation and storage increase sharply.This thesis uses a method to reduce the amount of computation and storage when calculating the electromagnetic scattering problem of finite periodic structure.In this thesis,when the electromagnetic scattering of various finite-period structural elements is calculated by the moment of method,a suitable entire domain basis function is selected for each unit instead of the traditional subdomain-based basis function.It not only ensures the calculation accuracy,but also reduces the number of elements of the impedance matrix.The amount of calculation for solving the matrix equation and the storage of unknown parameters are reduced.After calculating the electromagnetic scattering of various elements,the various units are combined into finite periodic structures.Then we used the Toeplitz property of the impedance matrix to solving the matrix equation by the Conjugate Gradient-Fast Fourier Transform method.The results show that the accuracy of this method is accurate,and the amount of calculation and data stored in the calculation process are significantly reduced compared with the traditional method based on the domain-based basis function.It provides the basis for further research on fast algorithms for electromagnetic scattering of finite-period structures in the future.