Key Techniques Of Parallel Method Of Moments In Analysis Of Large-scale Array And Radom

The analysis of scattering and radiation is of significance to the design of complex systems,such as large-scale antenna array,airborne antenna and radome.However,since the accurate simulation of electrically large targets with detailed structures requires large memory and computational amounts,the simulation remains one of the challenging subjects in computational electromagnetic.Recently,the rapid development of domestic high-performance supercomputers provides us with powerful foundation of precisely simulating electromagnetic problems in national major strategic projects.This thesis enhances the ability of Method of Moment(MoM)by using parallel technique on supercomputers and solves many engineering problems in key projects.Aiming at multi-scale problems like airborne antenna,large-scale conformal array and radome,this thesis studies multiple ways to improve computational efficiency,such as the accelerating algorithm,cooperative computing and box extrapolation method based on equivalent source,among which cooperative computing can' solve airborne antenna analysis effectively.This thesis deduces general integral equation which can be applied to analyzing composite structures of homogeneous materials from equivalence principle.In order to realize the matched source and load in MoM,the theory of waveports is studied and waveport is achieved in higher-order basis function MoM,which can be utilized to analyze filters and waveguide traveling wave antenna.Aiming at the most frequently used RWG basis function and higher-order basis function(HOB),this thesis compares the advantages and disadvantages of them in mesh generation,accuracy and resource consumption,analyzes the adept application scenarios and offers instruction to the selection of basis function in practical engineering applications.In order to enlarge the problem scale of MoM,this thesis introduces large-scale parallel technique and Multi-level Fast Multipole Algorithm(MLFMA).For problems of complex structures not adaptive to fast algorithms,this thesis adopts large-scale parallel scheme to solve problems.The parallel efficiency of the MoM utilizing the two basis functions was measured on two general platforms,HPC in Xidian University and "Tianhe-2" in Guangzhou Supercomputer Center and one domestic platform "Sunway Blue Light" inJinan National Supercomputer Center.The RWG-MoM works at 480 cores and parallel efficiency more than 80%when the parallel scale reaches 1440 CPU cores in Xidian HPC.The HOB-MoM works at 2,500 cores and parallel efficiency more than 45%when the parallel scale reaches 100,000 CPU cores on "Tianhe-2".The parallel efficiency reaches 70%when RWG-MoM extends from 1,024 cores to 10,000 cores,while the parallel efficiency reaches 65%when HOB-MoM extends from 600 cores to 12,000 cores on "Sunway Blue Light" platform.This thesis also offers the memory usage range which can give full play to the performance in these three computing platforms by testing and analyzing.Aiming at multi-scale problems,this thesis establishes unified architecture of multi-algorithm cooperative computing to take full advantage of different algorithms and improve computation efficiency.Complex problems are divided into several regions according to the structure,material,feed,etc.The most suitable algorithm of each region can be chosen and regions are managed as child notes according to network topology.The topology of different regions isolates with each other,while the coupling turns into near field and is conveyed by network bus.Cooperative algorithm is an efficient way to deal with multi-scale electrically large problems.It can analyze platform level problems like airborne antenna rapidly and efficiently by combining MoM with MLFMA.In engineering applications of parallel MoM,focusing on large-scale conformal arrays,the box extrapolation method based on equivalent source is proposed.This method first adopts parallel MoM to extract a sub-array equivalent source which is big enough,then rapidly syntheses the radiation pattern by translating and rotating the equivalent source.This thesis analyses a conformal array with more than 70,000 units,verifying the high efficiency when dealing with large arrays.This thesis also adopts parallel HOB-MoM and supercomputer to extract the eigen solution of an array with radome,synthesize the different beams by using eigen solution on work stations and compensates for the loss of electrical property by optimizing the feeding.This method realizes the accurate simulation and optimization of radome integrated.The numerical results in this thesis are of great reference value to practical engineering.