Computational electromagnetics

About: Computational electromagnetics is a research topic. Over the lifetime, 6412 publications have been published within this topic receiving 113727 citations. The topic is also known as: Electromagnetic field analysis.

A study of mlfma for large-scale scattering problems

Abstract: This research is centered in computational electromagnetics with a focus on solving large-scale problems accurately in a timely fashion using first principle physics. Error control of the translation operator in 3-D is shown. A parallel implementation of the multilevel fast multipole algorithm (MLFMA) was studied as far as parallel efficiency and scaling. The large-scale scattering program (LSSP), based on the ScaleME library, was used to solve ultra-large-scale problems including a 200λ sphere with 20 million unknowns. As these large-scale problems were solved, techniques were developed to accurately estimate the memory requirements. Careful memory management is needed in order to solve these massive problems. The study of MLFMA in large-scale problems revealed significant errors that stemmed from inconsistencies in constants used by different parts of the algorithm. These were fixed to produce the most accurate data possible for large-scale surface scattering problems. Data was calculated on a missile-like target using both high frequency methods and MLFMA. This data was compared and analyzed to determine possible strategies to increase data acquisition speed and accuracy through multiple computation method hybridization.

Skin-Effect Loss Models for Time- and Frequency-Domain PEEC Solver

Abstract: A challenging and interesting issue for the solution of large electromagnetic problems is the efficient, sufficiently accurate modeling of the broadband skin-effect loss for conducting planes and 3-D shapes. The inclusion of such models in an electromagnetic (EM) solver can be very costly in compute time and memory requirements. These issues are particularly important for the class of signal, power, and noise integrity (NI) problems. In this paper, we concentrate on partial element equivalent circuit (PEEC)-type methods which are suitable for the solution of this class of problems. Progress has been made recently in the design of skin-effect models. The difficult issues are broadband frequency-domain or time-domain problems. These models are considered in this paper. We present several solution methods, and we compare results obtained with these approaches.

Modeling Vacuum Electronic Devices Using Generalized Impedance Matrices

Abstract: We have developed a general approach to modeling a large class of vacuum electronic devices (VEDs) by using impedance matrices to characterize the circuit structure. Our approach can treat VEDs that have an arbitrary number of interaction gaps, severs, and input and/or output ports that may incorporate arbitrarily complex matching and/or tuning elements and windows. To find the impedance matrix for a given structure, we use the computational electromagnetics 3-D finite-element code HFSS to compute the response of the entire structure to an excitation of each individual port and gap. We define voltages and currents as certain integrals over the electric and magnetic fields, respectively, the ratios of which are elements of the generalized impedance matrix. This matrix is then imported into a beam-wave interaction code, which is used to compute VED performance (gain, output power, bandwidth, and so on). We have implemented this capability in a new 2-D code TESLA-Z, which has been verified by comparison with the large-signal code TESLA-FW and then validated by comparison with measured data from a Ka-band folded-waveguide power-booster TWT. Similar capability was also implemented in the 1-D interaction code CHRISTINE-CC.

Variational Integrators for Maxwell's Equations with Sources

Abstract: In recent years, two important techniques for geometric numerical discretization have been developed. In computational electromagnetics, spatial discretization has been improved by the use of mixed finite elements and discrete differential forms. Simultaneously, the dynamical systems and mechanics communities have developed structure-preserving time integrators, notably variational integrators that are constructed from a Lagrangian action principle. Here, we discuss how to combine these two frameworks to develop variational spacetime integrators for Maxwell's equations. Extending our previous work, which first introduced this variational perspective for Maxwell's equations without sources, we also show here how to incorporate free sources of charge and current.

A block iterative algorithm for 3-D electromagnetic modeling using integral equations with symmetrized substructures

Abstract: The integral equation method is in many cases a cost effective way of modeling the electromagnetic response of 3-D conductivity structures. Yet the requirements on computer storage and on computation time in forming and inverting the scattering matrix limit its applications for large structures.