Thomas Weiland

Learn More
In the eld of computational electrodynamics the discretization of Maxwell's equations using the Finite Integration Theory (FIT) yields very large, sparse, complex symmetric linear systems of equations. For this class of complex non-Hermitian systems a number of conjugate gradient-type algorithms is considered. The complex version of the biconjugate gradient(More)
A new flexible subgridding scheme for the Finite Integration Technique is presented, which can be applied for the numerical simulation of electromagnetic phenomena in static, time and frequency domains as well as for the eigenmode computation. Numerical simulations both in the static as well as in the high frequency regime are presented to give evidence of(More)
1098-4402= The Yee finite-difference time domain method (FDTD) is commonly used in wake field and particle-incell simulations. However, in accelerator modeling the high energy particles can travel in vacuum faster than their own radiation. This effect is commonly referred to as numerical Cherenkov radiation and is a consequence of numerical grid dispersion.(More)
Mathematicians have proven that few specific collocation methods provide stable numerical solution for the delay differential equations provided the accuracy order of the finite difference approximation matches to that of the temporal interpolation. To adjoin this important conclusion to the development of stable time-domain field integral equation-based(More)
For the numerical solution of complex eigenvalue problems, arising with gyrotropic materials in resonators, the Jacobi-Davidson method is considered. In this paper the correction equation, which has to be solved within the Jacobi-Davidson method, is simplified and several preconditioning strategies, including also a multigrid scheme, are compared for the(More)
This paper presents a numerical procedure applied to the modeling of double negative metamaterial (MTM) structures. At the unit-cell level, the properties of the MTM are described by the extracted isotropic constitutive parameters, dispersion diagrams, and higher order modes analysis. The information gathered at the unit-cell level is used to characterize(More)