International Journal of Numerical Modelling: Electronic Networks, Devices and Fields
We have demonstrated that an optical correlator, based on superimposed Bragg gratings, can be used as all‐optical multi‐wavelength header recognition in optical packet switching networks. The proposed correlator is composed of two superimposed gratings in conjunction with variable delay lines. These superimposed Bragg gratings are used to demultiplex and multiplex the wavelength components of multi‐wavelength...
In this paper, the hierarchical high‐order basis functions on tetrahedrons are introduced to the Crank–Nicolson (CN) finite‐element time‐domain (FETD) with the 3D Maxwell equations for analysis of the microwave circuit structures. Whitney 1‐form high‐order hierarchical basis functions are used to expand the electric field and Whitney 2‐form high‐order hierarchical basis functions for the magnetic...
This paper proposes general eigenvalue‐based passivity tests for descriptor state space systems, extending the already available tests for standard state space systems. Generalized eigenvalue tests are proposed to identify passivity violations in the positive‐real and bounded‐real cases. The important practical case of singular descriptor state space systems is also treated. The proposed passivity...
A numerical scheme is presented for the time‐domain finite‐element modeling of an electrically and magnetically lossy and dispersive medium in the dual‐field domain‐decomposition method. Existing approaches for modeling doubly lossy and dispersive media are extended to the dual‐field case, yielding a general dual‐field domain‐decomposition scheme for modeling large‐scale electromagnetic problems involving...
We propose a novel parametric macromodeling method for systems described by scattering parameters, which depend on multiple design variables such as geometrical layout or substrate features. The new concept of internal nonexpansivity for bounded real systems is introduced. It is used in combination with suitable interpolation schemes to interpolate a set of state‐space matrices, and hence poles and...
Comprehensive studies of ultra‐wideband pulses and electromagnetic coupling on printed coupled lines have been performed using full‐wave 3D finite‐difference time‐domain analysis. Effects of unequal phase velocities of coupled modes, coupling between line traces, and the frequency dispersion on the waveform fidelity and crosstalk have been investigated in detail. To discriminate the contributions...
In this paper, a propagator matrix method applied to logging‐while‐drilling tools is introduced and extended to deal with the anisotropic and radially inhomogeneous earth formations. This method expands the Maxwell's equations in the transverse direction, constructs the relationship between propagator matrix and reflection matrix, and obtains the solution by using the reflection matrix. We systematically...
The dual‐primal finite‐element tearing and interconnecting (FETI‐DP) method is combined with the tree‐cotree splitting (TCS) method to expand the capability and improve the efficiency of the finite‐element analysis of electromechanical devices. With the FETI‐DP method, an original large‐scale problem is decomposed into smaller subdomain problems and parallel computing schemes are then employed to...
In this paper, a corrective economic dispatch problem formulation for distributed generators in a microgrid is presented, which considers the transition from grid‐connected operation to islanded operation. Various constraints related to the operation of a microgrid are modeled, such as spinning reserve requirement for the variation of load demand and the output of intermittent sources, the flow limits...
This paper presents a method for the evaluation of capacitance and charge distribution of a dielectric coated metallic disk and a dielectric coated metallic hollow truncated cone with top and bottom cover plates using the method of moments (MoM) based on pulse basis function and point matching. Boundary conditions for the potential on the conductor surfaces and continuity of the normal component of...
A modal finite‐difference time‐domain (FDTD) method is extended for the analysis of ridged cavities, which are uniform in the z‐direction. Assuming that the end surfaces of cavity are the perfect conductor, thus, the fields along the z‐axis can be described by kz. Therefore, three‐dimensional (3‐D) problems can be simulated by the use of a two‐dimensional model. Besides, to achieve a faster computation,...
In this paper, we employ the Reduced Surface Field technique in metal semiconductor field effect transistors (MESFETs) by a P‐type region above the active layer near gate (PR‐MESFET). Electric field distribution can be made more uniform by a new depletion region in the active layer of the proposed structure that is created by a P‐type region. Therefore, the electric field peak at the gate edge decreases,...
Power amplifier asymmetry is captured by a behavioural model that contains multiple slices representing the amplifier's nonlinearity and long‐term, that is low frequency, memory. The simulation is performed entirely in the time domain, and the expense associated with performing a purely transient radio frequency (RF) simulation is circumvented by scaling down the carrier frequency by two orders of...
The LDG2 viscous flux formulation was recently developed by Kannan and Wang for the spectral volume setting. The LDG2 scheme is a variant of the more popular LDG formulation and retains the attractive features of the latter. In addition, it also displays higher degree of symmetry and accuracy than the LDG approach and has a milder stability constraint than the original formulation. In this paper,...
The critical tool of modeling irregularly shaped perfect conductors is developed for the extended‐stencil high‐order two‐dimensional M24 variant of the finite‐difference time‐domain (FDTD) method. Two standard FDTD conformal approaches are analyzed and successfully extended to work accurately with M24. They both afford higher order convergence with respect to mesh density than a previously developed...
A physically based power PiN diode model is presented. Eigen value internal approximation method is used to solve the ambipolar diffusion equation. This model is implemented in SIMPLORER circuit simulator using VHDL‐AMS language. The proposed model can be used in both circuit simulators and the optimization of a given power PiN diode. Good agreement is obtained by comparing the results of the suggested...
We present a versatile technique for constructing fast microwave component models at a low computational cost. Our modeling procedure consists of two stages: (i) kriging interpolation of coarsely discretized electromagnetic simulation data of the device under consideration and (ii) enhancing the kriging model by using space mapping and a limited amount of high‐fidelity electromagnetic simulation data...
Comparative analysis of different, new gas sensing materials in surface acoustic wave chemical sensors is presented. Different gas sensing materials as polyaniline (PANI), Teflon AF 2400, polyisobutylene (PIB), polyepichlorohydrin (PECH) are considered. They are chosen according to the type of gas to be detected and the desired accuracy: Teflon AF 2400 thin film for the detection of CO2, PANI nanocomposites...
The connection of small‐scale embedded generation to the grid may influence the frequency and voltage stability of the power system. A load‐frequency control technique for systems with high penetration of small‐scale wind generation is proposed. The proposed controller has been successfully implemented and tested using PSCAD/EMTDC (PSCAD Power System Simulation, HVDC Research Centre, Manitoba, Canada)...