Research On Modeling Method Of Electromagnetic Radiation/scattering For Complex Array Antennas

The accurate and efficient analysis of large and complex arrays with periodic structures,such as scattering calculations for frequency-selective surfaces and radiation/scattering calculations for finite antenna arrays,and so on,attaches great importance to the military and civilian industries.There are certain difficulties in the accurate simulation of such models.Because of the increase of array size and cell complexity,the computational resources required to solve the large-scale complex periodic array far exceed the hardware conditions available at this stage.Also,integrated electromagnetic analysis is of great interest in practical engineering,such as large-scale planar periodic array structures carrying aircraft targets or low scattering carriers.In this thesis,firstly,the characteristic subdomain method is introduced based on the finite element method to avoid the storage and computation of repetitive quantities in the calculation of large-scale planar periodic array structures.Secondly,the performance of the integral equation is improved by replacing the inner iterative of the boundary metal subregion processing with the strong admissibility skeletonization factorization method.Thus,the research on modeling method of electromagnetic radiation/scattering for complex array antennas is carried out in the finite element boundary integral domain decomposition method(FE-BI-DDM).The main work is subdivided into the following two areas:1.The characteristic subdomain method in the FE-BI-DDM algorithm is improved to avoid the storage and calculation of repetitive quantities in terms of finite element processing.Firstly,the antenna radiation problem is not directly excited by plane wave as in scattering calculations.For the radiation problem,the waveguide port feed model is introduced.Secondly,the characteristic subdomain method is described from ideological starting point to the specific implementation details in the program.Finally,in a specific numerical example,it can be seen that the characteristic subdomain method can significantly reduce peak memory,decrease the program solution running time,and improve the overall performance efficiency while not changing the algorithm solution accuracy through the calculation of electromagnetic radiation/scattering problems such as large-scale frequency selective surface(FSS)and planar periodic array antenna.2.A hybrid solver combining iterative solution and fast direct solution is proposed to reduce the time consumption of numerical computation.The method specifically replaces the generalized minimal residual(GMRES)inner iterative part of the FE-BIDDM algorithm dealing with the integral equation of the boundary metal subregion with the strong admissibility skeletonization factorization method(SASF).Firstly,the generalized minimal residual(GMRES)method used in the procedure is reviewed and its restarted version is briefly described.Secondly,the strong admissibility skeletonization factorization method is described in detail,in terms of both matrix compression and skeleton decomposition.Finally,it can be seen from the specific numerical examples that a hybrid solver dealing with the integral equations of the boundary metal subregion with the strong admissibility skeletonization factorization method can reduce the program running time,compared to the single use of iterative methods.