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Comparison of Different Methods for Calculating Gyrotron Quasi-Optical Mode Converters

JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES 2013年第1期34卷 62-70页

作者： Gashturi, A. P. Chirkov, A. V. Denisov, G. G. Paveliev, A. B. Russian Acad Sci Inst Appl Phys Nizhnii Novgorod 603950 Russia

This paper presents the use of combination of three methods for calculation and synthesis of high-efficiency microwave mode converters, such as radiators of gyrotrons. The analytical method yields immediate estimates of mode converter dimensions, the Scalar Integral Equation (SIE) allows one to synthesize efficiently the optimal profile of the mode converter, and the most accurate Electric Field Integral Equation (EFIE) is used to check all transmission characteristics of the converter including calculations of reflection and cross-polarization. The combination of these three methods is an optimal for the mode converter design. Just so the launcher was designed for a quasi-optical mode converter used in the 60 GHz gyrotron in the TE7,3 operating mode. The simulation results agree well with the measured data. The paper also presents for the first time an accurate derivation of the SIE method.

关键词： Gyrotron Launcher Microwave measurements Complement method Scalar Integral Equation Electric Field Integral Equation multilevel fast multipole algorithm

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Linear-linear basis functions for MLFMA solutions of magnetic-field and combined-field integral equations

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2007年第4期55卷 1103-1110页

作者： Ergul, Ozgur Gurel, Levent Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey

We present the linear-linear (LL) basis functions to improve the accuracy of the magnetic-field integral equation (MFIE) and the combined-field integral equation (CFIE) for three-dimensional electromagnetic scattering problems involving closed conductors. We consider the solutions of relatively large scattering problems by employing the multilevel fast multipole algorithm. Accuracy problems of MFIE and CFIE arising from their implementations with the conventional Rao-Wilton-Glisson (RWG) basis functions can be mitigated by using the LL functions for discretization. This is achieved without increasing the computational requirements and with only minor modifications in the existing codes based on the RWG functions.

关键词： basis functions combined-field integral equation magnetic-field integral equation multilevel fast multipole algorithm

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An Iterative Hybrid JMCFIE-MSIE-PO Method for Analyzing EM Scattering From Complex Target Above Rough Surface

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2021年第5期20卷 633-637页

作者： Zou, Gao Xiang Tong, Chuang Ming Sun, Hua Long Peng, Peng Song, Tao Air Force Engn Univ Xian 710051 Peoples R China

An iterative hybrid method is proposed for analyzing the electromagnetic (EM) scattering from complex target above rough surface. First, the electric/magnetic current-combined field integral equation (JMCFIE) is formulated to calculate the EM scattering from the complex target combining conductor and multiple dielectric objects. Then, the single integral equation (SIE) method for multiple dielectric objects in the complex target (MSIE) is applied to reduce one-half of the unknowns in dielectric regions, and the hybrid JMCFIE-MSIE method is formulated. Afterward, physical optics (PO) approximation is employed for computing the EM scattering on the rough surface, and the iterative hybrid based on the combination of JMCFIE-MSIE and PO is derived for composite scattering from complex target above rough surface. Furthermore, the multilevel fast multipole algorithm is utilized to accelerate the matrix-vector multiplications in the computation process. The equivalent edge currents method is applied to meliorate the result. Finally, the validation and applicability of the proposed iterative solution are demonstrated by several numerical examples.

关键词： Dielectrics Surface roughness Rough surfaces Conductors Electromagnetic scattering Integral equations Surface treatment Combined field integral equation complex target multilevel fast multipole algorithm physical optics rough surface single integral equation

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Volume integral equation equivalence principle algorithm domain decomposition with body of revolution equivalence surface

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IET MICROWAVES ANTENNAS & PROPAGATION 2018年第3期12卷 375-379页

作者： Li, Mengmeng Zhuang, Tao Chen, Rushan Nanjing Univ Sci & Technol Dept Commun Engn Nanjing Jiangsu Peoples R China

A novel equivalence principle algorithm (EPA) domain decomposition method previously for the surface integral equation is explored for volume integral equation in this work. The whole object is decomposed into several subdomains, the equivalence spheres are automatically produced to enclose each subdomain. The Rao-Wilton-Glisson (RWG) and body of revolution (BoR) basis functions are defined on the equivalence sphere surface. The equivalence currents defined on the RWG basis functions are evaluated with multilevel fast multipole algorithm, and then the currents defined on the RWGs can be projected onto the BoR basis functions. Compared with surface integral equation EPA-BoR algorithm, the ratio of the number of average original unknowns in each subdomain with respect to the equivalence unknowns is relatively larger, which leads to significant reduction of computations. Numerical simulations validate the accuracy and efficiency of the proposed method.

关键词： integral equations decomposition equivalence classes numerical analysis volume integral equation equivalence principle algorithm domain decomposition method Rao-Wilton-Glisson method RWG method body of revolution basis function BoR basis function equivalence sphere surface multilevel fast multipole algorithm surface integral equation EPA-BoR algorithm numerical simulation

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Numerical analysis of local interpolation error for 2D-MLFMA

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2003年第1期36卷 8-12页

作者： Ohnuki, S Chew, WC Univ Illinois Dept Elect & Comp Engn Ctr Computat Electromagnet Urbana IL 61801 USA

The error control of local interpolation for a 2D MLFMA will be discussed. The way to select proper parameters is proposed in terms of both numerical accuracy and computational cost. Satisfying the conditions derived in this paper, error can be controlled at the some level as global interpolation, and the computational cost becomes less expensive than the global one. (C) 2003 Wiley Periodicals, Inc.

关键词： multilevel fast multipole algorithm error analysis interpolation error

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Rigorous Solutions of Electromagnetic Problems Involving Hundreds of Millions of Unknowns

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IEEE ANTENNAS AND PROPAGATION MAGAZINE 2011年第1期53卷 18-27页

作者： Erguel, Oezguer Gurel, Levent Univ Strathclyde Dept Math & Stat Glasgow Lanark Scotland Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey Bilkent Univ Computat Elect Res Ctr BiLCEM TR-06800 Ankara Turkey

Accurate simulations of real-life electromagnetic problems with integral equations require the solution of dense matrix equations involving millions of unknowns. Solutions of these extremely large problems cannot be easily achieved, even when using the most powerful computers with state-of-the-art technology. Hence, many electromagnetic problems in the literature have been solved by resorting to various approximation techniques, without controllable error. In this paper, we present full-wave solutions of scattering problems discretized with hundreds of millions of unknowns by employing a parallel implementation of the multilevel fast multipole algorithm. Various examples involving canonical and complicated objects, including scatterers larger than 1000 lambda, are presented, in order to demonstrate the feasibility of accurately solving large-scale problems on relatively inexpensive computing platforms.

关键词： Electromagnetic fields electromagnetic scattering integral equations iterative methods parallel algorithms multilevel fast multipole algorithm

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MLFMM techniques for efficient analysis of random array configuration for SKA radio telescope

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JOURNAL OF ENGINEERING-JOE 2017年第12期2017卷 656-658页

作者： Padhi, Shantanu K. Chalmers Univ Technol Biomed Electromagnet Grp Dept Elect Engn E2 SE-41296 Gothenburg Sweden Thayer Sch Engn Dartmouth Microwave Imaging & Spect Grp Hanover NH 03755 USA

The implication of multilevel fast multipole algorithm (MLFMM) is applied to the analysis of large antenna array of the dual-polarised log-periodic dipole antenna in the presence of dielectric half-space and arranged in a random array configuration for square kilometre array (SKA) radio telescope. The MLFMM is applied to accelerate the matrix-vector product operations. The findings are compared with the results obtained by standard method-of-moment solver. Numerical results are given to demonstrate the accuracy and capability of this algorithm.

关键词： dipole antenna arrays astronomical techniques radiotelescopes square kilometre array radio telescope dielectric half-space dual-polarised log-periodic dipole antenna multilevel fast multipole algorithm SKA radio telescope random array configuration MLFMM techniques

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Analysis of Scattering by a Ship and Its Wake on Wind-Driven Ocean Surface 5

Analysis of Scattering by a Ship and Its Wake on Wind-Driven...

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The 5th International Symposium on Electromagnetic Compatibility

作者： Hai-Li Zhang Xing-Yue Guo Ming-Yao Xia School of Electronic Engineering University of Electronic Sci.and Tech.of China School of Electronics Eng.and Computer Sci.Peking University

ISBN: (纸本)9781509051861;9781509051854

A new procedure for analysis of scattering by a ship and its wake on ocean-like surface is presented.A smoothing transition technique is adopted to truncate the infinite *** scattered field is expressed as two parts:one part is a given field containing the contribution from the boundless flat surface,while the other part is the difference field due to the ship and the finite rough *** fast multiple algorithm(MLFMA) is incorporated to accelerate the *** of the proposed method has been provided by comparing with the small slope approximation(SSA) method.

关键词： multilevel fast multipole algorithm ocean surface scattering ship small slope aproaxiamtion wake

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Efficient MLFMA analysis of coupled rectangular and circular apertures in a finite screen

Efficient MLFMA analysis of coupled rectangular and circular...

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IEEE MTT-S International Microwave Symposium

作者： Rullhusen, I Arndt, F Univ Bremen Microwave Dept D-28359 Bremen Germany

ISBN: (纸本)0780376951

A multilevel fast multipole algorithm (MLFMA) is introduced for the efficient analysis of coupled rectangular and circular apertures of different size within a finite conducting screen. The electric field integral equation (EFIE) is written in terms of mixed potential formulation. Aperture waveguide modal eigenvectors and Rao-Wilton-Glisson (RWG) functions for triangular patches are utilized as basis functions for the magnetic and electric surface current densities, respectively. For the resulting method-of-moments (MoM) solution, a MLFMA is formulated which includes the modal excitations of the coupled rectangular and circular apertures. This leads to significantly reduced computational complexity for these kinds of problems. The method is verified by available measurements and reference calculations.

关键词： electric field integral equations method of moments waveguide theory circular waveguides rectangular waveguides coupled rectangular-circular waveguide aperture multilevel fast multipole algorithm finite conducting screen electric field integr MLFMA electric field integral equation (EFIE) circular waveguides METHOD OF MOMENTS waveguide theory Rectangular waveguides CIRCULAR APERTURE apertures

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Analysis of three-dimensional dielectric scatterer with solenoidal basis functions and iterative solvers

Analysis of three-dimensional dielectric scatterer with sole...

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6th IEEE International Conference on Electro/Information Technology (EIT 2006)

作者： Fan, Z. H. Chen, R. S. Wang, D. X. Yung, Edward K. N. Natl Univ Sci & Technol Nanjing 210094 Jiangsu Prov Peoples R China City Univ Hong Kong Dept Elect Engn Hong Kong Peoples R China

ISBN: (纸本)9780780395930

The solenoidal basis functions proposed by Carvalho and Mendes, which are defined on tetrahedrons, are applied into multilevel fast multiple algorithm to analyze the electromagnetic scattering problem of the three-dimensional homogeneous or inhomogeneous dielectric objects. Necessary formulations for implementation are given in detail. Three popular Krylov subspace iterative methods, that is, conjugate gradient method (CG), bi-conjugate gradient method (BiCG), and general minimize residual (GMRES), are introduced to solve the resultant linear equations. We also introduce a novel iterative method-loose general minimize residual (LGMRES), which gives a little modification to GMRES, but promotes the convergence rate obviously. The results display that the LGMRES has a best performance, while CG is inefficient in the calculations for large electric-size using solenoidal basis functions method of moment.

关键词： volume integral equations solenoidal basis functions Krylov subspace iterative methods loose GMRES multilevel fast multipole algorithm

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