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.

In this paper, a novel approach is described to design an interdigital capacitor (IDC) using artificial neural networks (ANNs) and genetic algorithm (GA). The scattering parameters of the training samples are computed by the finite-difference time-domain (FDTD) and ANN is applied to describe the models of IDC. According to the engineering requirement, the dimensions of IDC can be designed with GA using the trained ANN models. This design procedure is proved to be time saving and of high accuracy.

In this paper, the electromagnetic wave scattering is analysed by the efficient Krylov subspace iterative fast Fourier transform (FFT) technique in terms of the electric field integral equation (EFIE) for a dielectric body of general shape, inhomogeneity, and anisotropy. However, when the permittivity of the scatter becomes large, the convergence rate of Krylov subspace iterative methods slow down. Therefore, the innerouter flexible generalized minimum residual method (FGMRES) is used to accelerate the iteration. As a result, nearly 10 times convergence improvement is achieved for high permittivity cases. Copyright

Currently extended finite-difference time domain (FDTD) formulations require the permittivity and conductivity to be independent of frequency. However, for many real materials of interest, these parameters vary significantly with frequency. The extended frequency-dependent finite-difference time domain (FD)2TD method makes it possible to analyze hybrid integrated circuits with lumped element within dispersive medium by combining lumped parameters (R, C, or L) and frequencydependent dielectric substrate in the algorithm. This method allows the full-wave analysis of virtually hybrid integrated circuits and gets parameters with a wide frequency range with one simulation.

A gradient optimization technique along with a definition of cost function is applied to the CAD of the circulator with a magnetized ferrite sphere for millimeter wave communications. A three. dimensional Finite. Difference Time-Domain (FDTD) approach for the analysis of this ferrite sphere based microstrip circulator is presented. The topology of the structure is enforced at each sted Of optimization and its physical dimensions are used as optimization variables. The cost function is defined using location of zeros and poles of the circulator's transmission, isolation. and reflection functions. Numerical tests show that theoptimization process converges from an arbitrarily selected starting point with the new definition of the cost fimction.