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The fine analysis of rotor losses of induction motors requires separation of the slip- and high-frequency electromagnetic quantities under load conditions. However, the conventional method involves a full slip-cycle finite element simulation, which is very expensive in terms of CPU time and memory usage. To obtain a precise iron loss prediction with reduced time consumption, this paper proposes three...
Based on one dimensional first-order basis function, the construction process of the second and third-order scalar hierarchical basis functions in two dimensional case is given. The second and the third-order basis functions are applied to discontinuous Galerkin time domain (DGTD) algorithm. The influence of order of the basis function in accuracy of DGTD is analyzed.
This paper simulates scattering properties of metasurfaces by finite difference time domain(FDTD) method with generalized sheet transition conditions (GSTCs) to alleviate computational burden. It is found that a metasurface can be represented by the electric and magnetic polarization densities, which is related to electromagnetic field by GSTCs. The GSTCs are thereby implemented in 3D FDTD codes and...
A surface lumped circuit model is formulated for the discontinuous Galerkin time-domain modeling of devices with lumped elements. A leap-frog algorithm is used for time integration, resulting in an explicit and conditionally stable time-marching algorithm. A microstrip filter with four ports and two lumped elements is simulated to validate the proposed method.
This paper presents an accurate and efficient time-domain approach for analyzing the coupling of transient electromagnetic fields into cable systems with arbitrary linear networks at terminations. Some nonlinear elements in termination circuits are also considered. The approach is based on hybridization of three different methods. First, the discontinuous Galerkin time domain (DGTD) method is used...
PZFlex is a commercial FEA software that has been optimized for the ultrasound industry and is commonly used to design piezoelectric ultrasound transducers. However, PZFlex is not commonly used within the CMUT research field. Nevertheless, it has an explicit modeling approach allowing large structures like CMUT arrays to be modeled and its transient analysis intrinsically supplies non-linear and broadband...
We present a new finite-element time-domain (FETD) solver for analysis of axisymmetric devices based on discrete exterior calculus (DEC) and transformation optics (TO) concepts. The proposed FETD solver decomposes the fields into TEϕ and TMϕ modes, which are expanded by using appropriate set of (vector or scalar) basis functions. Utilizing DEC, trigono-metric orthogonality, and a leap-frog time-integrator,...
Accurate modelling of photonic systems has to allow for the treatment of complex geometries and unusual material properties. While the former suggests the use of unstructured measures in conjunction with high-order basis functions such as in traditional finite element approaches, the latter implies working within the time domain so that general nonlinearities and transient phenomena can be considered...
The photonic crystal (PhC) membrane represents a platform for planar integration of components, where cavities and waveguides may play a key role in realizing compact optical components with classical functionality such as switches, lasers, and amplifiers or quantum optical functionality such as integrated sources of quantum light. By leaving out a row of holes in an otherwise perfect PhC membrane...
In this paper, we present Padé approximation boundary conditions for domain truncation in time domain analysis using finite element (FEM) beam propagation method. The method removes the number of unknowns required for the conventional perfectly matched layer (PML). The line integral resulted from FEM discretization is treated by solving the one dimensional Helmholtz wave equation at domain ports....
The prediction of EMI sources in electrical and digital devices is not a simple task. In practice it is difficult to predict all the possible sources of EMI, from even relatively simple devices. This paper reviews and summarizes the possible EMI sources and the numerical electromagnetic modeling techniques that can be used to analyze these sources of electromagnetic interference. Although there are...
Coaxial lines are most widely used in driving microwave devices and antennas and in extracting outputs from them. In practice, both two processes involve a number of coaxial junctions which provide transfer characteristics dependent on the bandwidth of the microwave signal. Where transient characteristics of an antenna or any other device are to be investigated, the major prerequisite is to have a...
In this paper, we extend the recently introduced Finite Element Gaussian Belief Propagation (FGaBP) method beyond the scope of electrostatic problems, to address time-domain applications. The FGaBP inference algorithm was adapted to perform time-stepping computations based on the vector wave equation (VWE) discretized by the Newmark method. We validated the new algorithm using a reference finite element...
The traditional method to obtain the response of electromagnetic devices over a wide frequency range is to use a frequency sweeping method. However, this method is very time consuming, especially in time-domain analysis. In order to save the heavy computational time, a novel fast algorithm based on finite-element method (FEM) to obtain the response under different frequencies is therefore proposed...
This paper presents an analysis of the performances of competing approaches in the numerical solution of wave propagation problems in the time domain, with focus on the advantages of an approach based on a FD-TD scheme on two interlocked grids over known FIT and FEM approaches.
A semi-explicit time domain method for solving eddy-current problems is presented. The suggested method is based on the discontinuous Galerkin (DG) finite element approach and the H-Φ formulation of eddy-current problem. The DG-technique allows for explicit time stepping in electrically conducting domains without solving a large sparse ill-conditioned linear equation system. The H-Φ field formulation...
This contribution describes a methodology for computing compact time-domain models of electromagnetic devices containing Lorentz materials from finite-element systems in the frequency domain. The procedure starts with projection-based model-order reduction, to downsize system dimension. The resulting reduced-order model is transformed to the time-domain and leads to a state-space representation. The...
In this paper, a Discontinuous Galerkin Time-Domain (DGTD) method is used to model full Ground Penetrating Radar (GPR) scenarios. The bi-static GPR is made of two identical Vivaldi antennas, which are accurately modeled in front of a sand box in order to detect and localize some buried objects. Our approach is validated by comparison with either synthetic data provided by CST-MWS or experimental data...
A perturbation approach is used to derive surface impedance boundary conditions (SIBCs) for nonlinear magnetic conductors described by means of Brauer's model [1]. A new technique is proposed to solve the nonlinear diffusion equation of the magnetic field in conductive media and then its solution is coupled with a BEM formulation for the case of parallel magnetic conductors in terms of E and B fields.
In this digest a universal approach for solving multirate partial differential equations (MPDEs) is presented. Taking advantage of already known concepts in literature, standard finite element hat functions are used to achieve an efficient solution of a multirate problem in time-domain. The MPDE is solved by a Galerkin-ansatz with hat functions in the fast time-scale and using conventional time discretization...
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