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A combined algorithm of the edge-based finite-element method (FEM) and the short-open calibration (SOC) technique is presented in order to analyze periodic structures. The computational domain is reduced to a unit cell through the use of waveguide simulators. To accurately predict the characteristics of periodic structures, the SOC technique is directly accommodated into the FEM formulation and removes unwanted parasitic errors brought about by the approximation of exciting sources. The developed FEM algorithm improves the accuracy of the solution and causes the rapid convergence of iterative solvers, when compared to the FEM combined with perfectly matching layers (PMLs) or absorbed boundary conditions (ABCs). The results for some periodic structures are given to show the accuracy and rapidity of the algorithm. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 427–430, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20844 [ABSTRACT FROM AUTHOR]

The anisotropic media and active properties of the perfectly matched layer (PML) absorbers significantly deteriorate the finite element method (FEM) system condition and as a result, convergence of the iterative solver is substantially slowed down. To address this issue, the symmetric successive over-relaxation (SSOR) preconditioning scheme is applied to the generalized minimal residual (GMRES) for solving a large sparse and non-symmetric system of linear equations resulting from the analysis of ferrite waveguide device by use of edge-based FEM. Consequently, this preconditioned GMRES (PGMRES) approach can reach convergence ten times faster than GMRES for the typical structures. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The multifrontal method is applied for solving a large, sparse, and unsymmetric system of linear equations resulting from the use of the edge-based finite-element method (FEM). The finite-element method combined with perfectly matched layers (PML) is given for simulation of microwave devices, and the combined algorithm of the multifrontal method is described. The electrical characteristics of typical waveguide devices such as the ferrite phase shifter and circulator are analyzed, and the calculated results are compared with those obtained from the literature. In order to demonstrate the efficiency of the multifrontal method, the computational time is compared with that of both successive overrelaxation (SOR) preconditioned conjugate-gradient (PCG) and conjugate-gradient methods (CG) for the phase shifter. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 76–81, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10521 [ABSTRACT FROM AUTHOR]

In this paper, ferrite waveguide devices are analysed by use of the edge-based vector finite element method combined with the short-open calibration (SOC) technique. The formulation with both permittivity and permeability tensors for tetrahedral vector elements is analytically given in terms of the electric field. The SOC technique is directly accommodated in the FEM algorithm and used to truncate the computational domain. The SOC technique removes or separates unwanted parasitics obtained by the approximation of the impressed voltage source and the inconsistency between different simulations. Several types of ferrite waveguide device are analysed and the results are compared with those of the available publications. A good agreement is observed between them. [ABSTRACT FROM AUTHOR]

In this paper, the application of the edge-based vector finite-element method combined with the short-open calibration (SOC) technique to three-dimensional waveguide discontinuity was presented. This SOC technique is directly accommodated in the FEM algorithm, and is used to truncate the computational domain. The developed FEM algorithm is applied to the modeling of dielectric-filled waveguide discontinuities that can be segmented into two distinct sections: the static model of feed lines, and the dynamic model of circuit discontinuity. The FEM is formulated in such a way that the port voltages and currents are explicitly represented through relevant network matrices. The SOC technique is used to remove or separate unwanted parasitics brought by the approximation of the impressed voltage source, as well as the problem of the resulting consistency between different simulations. Truncation of the computational domain by the SOC technique makes the iterative solvers for large sparse linear matrix equations from the FEM converge much faster than by perfectly matched layers (PML). Results for full-height/partially dielectric-filled waveguide discontinuities are very well compared with available publications. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 438–444, 2000. [ABSTRACT FROM AUTHOR]