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It is popular to use moving elements to improve heating uniformity during microwave heating under some situations. However, it is still a challenge to simulate moving elements during microwave heating due to the complexity of mathematical modeling. In this paper, a novel continuous algorithm based on implicit function and level set methods is developed to compute this heating process. By introducing the implicit function and level set methods, the moving region’s properties are set as a function of space coordinate and time, which means that the movement of the elements is represented by the variation of the parameters. In addition, with the coordinate transformation, the coupling process of electromagnetic field and heat transfer in microwave heating can be performed. A 2-D applicator model and a 3-D applicator model with a rotating turntable are used to illustrate the proposed method in detail. Experiments are also conducted to testify the validity of the proposed method. The results obtained by the proposed method are in accordance with those obtained by experiments. Moreover, compared with conventional methods, the proposed method is more accurate and efficient. [ABSTRACT FROM AUTHOR]

This paper presents a new physical model for shielded slow-wave coplanar waveguide structures. This lossy electrical model is based on physical behavior of the transmission lines. It allows a better understanding of the losses distribution along the structure. The ohmic losses in the coplanar strips, as well as the ohmic losses and the eddy current losses in the floating shield strips are studied for transmission lines having different geometrical dimensions and hence electrical characteristics. The model is then validated on different CMOS technologies and leads to the efficient optimization of the slow-wave transmission lines, especially concerning the floating shield dimensions. [ABSTRACT FROM AUTHOR]

Modeling the combined electromagnetic (EM)/quantum transport problem in graphene circuits requires the development of novel concepts and novel unified tools. In this paper, we further explore the correlation between Dirac and Maxwell equations, in the time domain, where we derive the transmission-line equations, valid for both EM and quantum current. This is a step forward toward an effective integration of the Dirac theory in the numerical simulation of EM field problems and introducing EM concepts and simulators to describe quantum transport. We show that the familiar Telegrapher's equations can be readapted in order to investigate the mechanisms that govern the space–time evolution of Dirac spinors; two significant examples, having a double quantum/EM meaning, are provided. Final considerations about associated quantum current have also been reported. [ABSTRACT FROM AUTHOR]

This paper presents a new neural-network method to describe the electromagnetic (EM) behavior at the interface between the substructures from an internally decomposed EM structure. A set of neural networks is used to represent the EM behavior of the substructure as seen from the interface. This allows EM coupling between substructures to be effectively represented. The method is developed in a finite-element environment. An EM transfer function matrix is formulated to produce training data, allowing neural networks to learn the spatial coupling between EM-field variables at various locations over the interface of the substructure. A new formulation is proposed where trained neural networks are integrated into the finite-element equation for efficient simulation of an overall EM structure. A technique is developed to allow the proposed model to be used with the mesh different from that in neural-network training. Examples show that the proposed method provides better accuracy than conventional neural-network approaches for modeling substructures from an internally decomposed EM problem. Using the proposed model also speeds up finite-element simulation. [ABSTRACT FROM AUTHOR]

This article presents a unified description of numerical methods for solving electromagnetic field problems. Traditionally, these methods are considered to be independent and alternative ways of solving Maxwell’s equations or equations derived therefrom. However, they all are projective approximations of the unknown solution by known expansion or basis functions with unknown amplitude coefficients that are determined using the so- called method of weighted residuals (MWR). This common feature forms the proposed unifying framework that may serve both as a systematic introduction to computational electromagnetics and as a way to provide insight into the nature, strengths, and limitations of the various algorithms used by present and future field solvers. For convenience, the fundamental equations and concepts of electromagnetics are summarized in order to facilitate the demonstration of the unified approach. Our aim is to provide students, designers, and researchers with a framework for developing new numerical algorithms, to guide users in the selection and application of electromagnetic design tools, and to foster informed engineering judgment. This article also serves as a review and summary of earlier theoretical works reported in different places and at different times. [ABSTRACT FROM AUTHOR]

The transmission-line matrix (TLM) method, in time domain, is extended to account for the presence of anisotropic and dispersive media in electromagnetic structures or devices. The model is thoroughly constructed by using Maxwell's equations that make it a unified general TLM formulation. Numerical results are compared with experimental measurements; hence, in the case of ferrite-based structures, validating the model and showing the accuracy of the approach. [ABSTRACT FROM AUTHOR]