Analysis Of The Large Antenna Arrays Based On Finite Element Method

Large antenna arrays are widely used in radar,air early warning and other systems.The performance of antenna arrays will greatly affect the performance of the entire system,playing an important role in the military and civilian fields.Numerical calculation of the electromagnetic fields is an effective method to analyze the electromagnetic characteristics of large antenna arrays.However,accurate calculations require enormous storage resources and computing resources.Therefore,analysis of large antenna arrays has always been a very challenging problem in computational electromagnetics.At present,most of the domestic numerical methods of electromagnetic analysis are serial or workstation-level calculations,and there is still much space of promotion in accurate and efficient simulation calculations of large antenna arrays.For the challenges faced by the simulation of large antenna arrays,such as the large electromagnetic models failed to fit accurately and discretely,computational resources aren't reasonably allocated,and approximate fast solutions aren't proposed,this thesis which base on the finite element method uses high-order basis functions,FE-IIEE(Finite ElementIterative Integral Equation Evaluation)mesh truncation technology,and parallel domain decomposition method to improve the ability and efficiency of the finite element method to analyze the large antenna arrays.For the antenna arrays with periodic characteristics,especially models composed of multiple media and complex structures,the finite element method has a strong ability to fit the model,so periodic boundary condition method based on finite element method can solve such problems well.In this thesis,the periodic boundary conditions and FE-IIEE are introduced,accelerating the convergence of the periodic Green's function through the Ewald transform,and using the infinite periodic structure to complete the approximate simulation of the far field pattern of the finite antenna array.Among them,FE-IIEE is a mesh truncation technology which is rarely used in China.This technology can set the absorbing boundary at a near position and has good convergence.For electromagnetic parameters such as the reflection coefficient and direction coefficient of a large antenna array with periodic characteristics,this method can be used to achieve rapid electromagnetic trend simulation.For large antenna arrays of any structure,this method introduces the domain decomposition method and parallel technology,and adopts the parallel domain decomposition strategy of MPI and Open MP to achieve fast and accurate solution for complex and large antenna arrays.In order to expand the scale of the finite element method in solving,combined with the hardware platform of the supercomputer,the simulation calculation of a large antenna array was completed on the computing cluster of Xidian University and Rubik's cube III.A large array antenna which generate exceeded 220 million unknowns is calculated with only 53 minutes using 8 512 GB memory computing nodes.In this thesis,many kinds of antenna arrays are simulated,such as a waveguide slot antenna and a microstrip antennas,etc.All of them realize the fast and accurate simulation of large-scale electromagnetic problems that are difficult to be solved by many commercial software.In summary,this thesis realizes the electromagnetic simulation of large-scale antenna arrays based on the finite element method by using infinite periodic boundary conditions,parallel domain decomposition method,and FE-IIEE mesh truncation technology,forming two independent methods that fits different needs for solving large antenna arrays: infinite periodic boundary conditions method and parallel domain decomposition method.It provides an effective analysis method with referential significance for the efficient electromagnetic analysis of the antenna arrays.