The Electromagnetic Modeling And Research On Efficient Algorithm For Complex Periodic Structure

Microstrip periodic structures are widely used in microstrip array antennas,electromagnetic bandgap structures,frequency selective surfaces and other fields.The periodic structure is mainly composed of a single resonant unit arranged in a certain form and has the same function of frequency selection as the filter,and mostly used on the radome to improve the performance of the antenna.The analytical model of periodic structure is mathematically difficult to express by formulas,so a specific algorithm is required in calculating the electromagnetic field of the periodic structure.In this paper,the numerical algorithm combining the periodic Green's function and the method of moments analyzes the periodic structure.Also,design a new type of periodic structure and antenna.The results of simulation and measurement meet the requirements.To calculate the new periodic structure with the numerical analysis algorithm and the results are slightly different from those of HFSS.The main contents of this paper are as follows:Green's function is a very important physical concept in periodic structures and the key to solve integral equations,and to study the characteristics of waves in periodic structures in the past.When applying periodic Green's function to the design and simulation of periodic microstrip structures,there are many problems such as great unknowns,difficulty in calculation and simulation.Because periodic Green's function has the form of summation of series and the original series converges very slowly or even not.In order to solve this problem,chose the Ewald method to accelerate the simulation of two-dimensional periodic Green's function in various acceleration algorithms,which achieves fast and efficient numerical calculation of periodic Green's function and accelerates the convergence of series sum at the same time.The design of multi-frequency broadband periodic structure has always been a difficult problem.Based on the Jerusalem prototype,this design changes the resonance frequency points of the structure to produce multiple resonance points by designing the coupling between the two-layer structure and the structure,and expand the bandwidth of the periodic structure.Finally,this paper designs a broadband,large incident angle,polarization-independent dualband frequency selective surface,and then applies the designed FSS structure to MIMO antenna to improve the antenna radiation parameters.Finally,calculate the scattering of FSS by the algorithm of this paper and compared with those of HFSS.The calculation results of the two are consistent.