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.

Fundamental implicit fdtd schemes for computational electromagnetics and educational mobile apps (invited review)

Abstract: This paper presents an overview and review of the fundamental implicit finite-difference time-domain (FDTD) schemes for computational electromagnetics (CEM) and educational mobile apps. The fundamental implicit FDTD schemes are unconditionally stable and feature the most concise update procedures with matrix-operator-free right-hand sides (RHS). We review the developments of fundamental implicit schemes, which are simpler and more efficient than all previous implicit schemes having RHS matrix operators. They constitute the basis of unification for many implicit schemes including classical ones, providing insights into their inter-relations along with simplifications, concise updates and efficient implementations. Based on the fundamental implicit schemes, further developments can be carried out more conveniently. Being the core CEM on mobile apps, the multiple one-dimensional (M1-D) FDTD methods are also reviewed. To simulate multiple transmission lines, stubs and coupled transmission lines efficiently, the M1-D explicit FDTD method as well as the unconditionally stable M1-D fundamental alternating direction implicit (FADI) FDTD and coupled line (CL) FDTD methods are discussed. With the unconditional stability of FADI methods, the simulations are fast-forwardable with enhanced efficiency. This is very useful for quick concept illustrations or phenomena demonstrations during interactive teaching and learning. Besides time domain, many frequency-domain methods are well-suited for further developments of useful mobile apps as well.

Proximity templates for modeling of skin and proximity effects on packages and high frequency interconnect

Abstract: Modeling the exponentially varying current distributions in conductor interiors associated with high frequency interconnect behavior causes a rapid increase in the computation time and memory required even by recently developed fast electromagnetic analysis programs. In this paper we describe a procedure to generate numerically a set of basis functions which efficiently represent conductor current variation, and thus improving solver efficiency. The method is based on solving a sequence of template problems, and is easily generalized to arbitrary conductor cross-sections. Results are presented to demonstrate that the numerically computed basis functions are seven to twenty times more efficient than the commonly used piece-wise constant basis functions.

Demonstration of time reversal methods in a multi-path environment

Abstract: Time reversal methods (TRM) offer a unique opportunity for solving the problem of electromagnetic (EM) wave propagation and focusing in a spatially varying (inhomogeneous) medium. While the concept of time reversal is new to the field of EM wave propagation, it has been applied in the area of acoustics and ultrasonics for several years (Fink, M. and Prada, C., Inverse Problems, vol.17, p.R1-38, 2001). In any finite size array that occupies a limited spatial area, the system is diffraction limited; however in acoustics, it has been shown that, in an inhomogeneous medium, a time reversal array is not always diffraction limited and can achieve super-resolution. Basically, scatterers near the transmitting array and/or focal point act as an extension of the array in the focusing process. The paper shows that the same phenomenon exists for EM waves. While the feasibility of applying TRM to EM problems has been demonstrated, many issues must be investigated and resolved before TRM can be implemented practically in a communications or radar imaging system.

Computational Time Reversal—A Frontier in Electromagnetic Structure Synthesis and Design

Abstract: Microwave component design by electromagnetic structure synthesis is attractive because the electromagnetic field has the inherent property to minimize loss, sensitivity to tolerances, and vulnerability to field breakdown. However, it is conceptually and computationally challenging, and its technical possibilities have thus been explored only tentatively so far. This paper introduces a first, but critical new step towards systematic electromagnetic structure synthesis, based on computational time reversal, and employing the time and space discrete transmission line matrix (TLM) method. The novelty of this paper resides in the exploitation of the scattering nature of the TLM model, which allows the near-field of a source or a scatterer to propagate into the far-field and back. By ignoring the conventional restriction that spatial wavelengths must always be much larger than the space discretization step, one can reconstruct multiple impulsive sources with the spatial and temporal resolution of the TLM algorithm. This crucial insight promises to be the key to a successful synthesis strategy. This paper describes the reconstruction of electromagnetic sources through computational time reversal, demonstrates the self-consistency of this procedure by means of a validation example, and outlines the next steps towards a full electromagnetic synthesis capability.

T-matrix method for biaxial anisotropic particles

Abstract: Using the T-matrix approach electromagnetic scattering by a biaxial anisotropic non-axisymmetric particle is studied. Electromagnetic fields inside the scatterer are expressed by a system of quasi-spherical vector wave functions which are derived by use of inverse Fourier transform. Using this expansion a solution of the light scattering problem in the framework of the null-field method with discrete sources is obtained. Numerical scattering results for ellipsoids and cubes are presented. For validation the calculation results obtained are compared with results from other light scattering programs such as DDSCAT and ADDA.