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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.
A discontinuous Galerkin time-domain (DGTD) method with a dynamic h-adaptation technique is presented in this paper. The adaptive Cartesian mesh (ACM) is employed so that the mesh elements get refined in real time of a simulation when the highly oscillatory electromagnetic pulse is passing by to achieve a desired resolution of the physics. When the pulse passes through or gets dissipated in the simulation...
In this work, we propose a simulation methodology that incorporates derating models of decoupling capacitors for power integrity analysis. The construction of the derating models of decoupling capacitors is based on the impedance measurement and curve fitting method. Three approaches of impedance measurement are compared and the most accurate one is selected to build the derating models. The curve...
A discontinuous Galerkin time-domain (DGTD) method is presented to simulate the coupled electromagnetic — plasma interactions in the modeling of high-power microwave (HPM) breakdown in air. For this multiphysics problem, the electromagnetic fields are governed by Maxwell's equations and the plasma is modeled as an electron fluid in continuum, which is governed by five-moment fluid equations. The non-Maxwellian...
The full dispersion characteristics, including phase and attenuation constants, of zero-phase-shift-lines (ZPSL) in a loop configuration are analyzed. Based on the phase and attenuation constants of the ZPSL unit cell, a ZPSL loop antenna is designed and optimized with an enhanced magnetic field intensity and an improved field distribution. Corresponding antenna prototypes are fabricated and measured...
A hybrid algorithm that combines the finite-element time-domain (FETD) method with the generalized scattering matrix (GSM) method is introduced to model resonant waveguide devices. The device is divided into several subdomains with each truncated with the waveguide port boundary condition (WPBC) to suppress resonance and therefore reduce the total number of time-marching steps. The subdomains are...
Specific Absorption Rate (SAR) is a measure of the electromagnetic exposure of portable devices imposed by regulatory agencies. In this paper, we model peak spatial-average SAR of multiple-antenna portable devices using a simple mixed quadratic function of the transmitted vector signal. The model takes into account the movement of location on peak SAR as the transmitted signal varies in amplitude...
A domain decomposition scheme is presented to analyze broadband scattering by deep open cavities using the finite-element time-domain (FETD) and generalized scattering matrix (GSM) methods. The cavity is decomposed into less resonant subdomains, and each subdomain is characterized by a GSM which is obtained by the fast Fourier transform of the FETD solutions. The subdomain GSMs are then cascaded to...
A coupled magnetic-thermal solver is developed for the modeling and simulation of nonlinear magnetic materials. By adopting a temperature-dependent dynamic hysteresis model, the magnetic loss is characterized and calculated from the solution of Maxwell's equations, which serves as the heat source in the thermal problem. By solving the thermal problem, the temperature shift is obtained and its effect...
An electromagnetic modeling approach is presented for the simulation of the specific absorption rate (SAR) in a human head at 60 GHz. Based on the strong skin effect, the human head model is simplified to reduce the computation cost. The multi-solver method based on the Robin transmission condition is employed to compute electromagnetic fields in the simplified human head. The SAR is calculated after...
An accurate and fast algorithm is proposed to evaluate the specific absorption rate (SAR) in an anatomically realistic human head model exposed to a wideband antenna. The algorithm is based on the discontinuous Galerkin time domain (DGTD) method using hybrid meshes. Hexahedral and tetrahedral meshes are used, respectively, to model the human head with a voxel data format and the wideband antenna with...
A multi-solver (MS) algorithm is accelerated on distributed computing systems to simulate the electromagnetic scattering from large and complex objects. In this algorithm, the targeted object with its background is decomposed into multiple subdomains which are modeled by either the finite element method or the method of moments. Different from conventional parallelized domain decomposition methods,...
In order to estimate the electromagnetic exposure under multi-antenna transmitters installed in portable devices, a low-order specific absorption rate (SAR) model is generalized to higher orders based on the Fourier series expansion for fast and accurate evaluation and prediction of SAR values as a function of phase differences among multiple transmitters. Numerical and experimental examples are given...
This paper presents a comprehensive reappraisal of the scattering, both backscattering and bistatic scattering, and emission of rough soil surface predicted by a well-established theoretical model, the advanced integral equation model (AIEM). Extensive numerical data simulated by approximate and numerically exact models as well as experimental datasets of well-characterized bare soil surfaces were...
We present two approaches for leveraging correlations in learning the utilities of non-cooperative agents' competing in a game: correlation and coalition utility learning. In the former, we estimate the correlations between agents using constrained Feasible Generalized Least Squares with noise estimation and then use the estimated correlations to generate a correlation utility function for each agent...
In this paper, we revisit the web browser model and propose the notion of fast-access browsing that incorporates lightweight, always-on web snippets, namely widget view, into web applications. This allows users to rapidly access web contents (i.e., within 200ms) similarly as they interact with notification on smartwatches. We analyze 90 smartwatch applications, identify the quick preview pattern,...
We describe a new method of parametric utility learning for non-cooperative, continuous games using a probabilistic interpretation for combining multiple utility functions—thereby creating a mixture of utilities—under non-spherical noise terms. We present an adaptation of mixture of regression models that takes in to account heteroskedasticity. We show the performance of the proposed method by estimating...
In this paper, a directional ultra-high frequency (UHF) near-field radio frequency identification (RFID) reader antenna is designed with an improved magnetic field distribution. Utilizing a high impedance surface (HIS) as a reflector, the proposed segmented grid-loop antenna shows a significant improvement compared with the benchmark example in terms of a more evenly distributed and stronger magnetic...
The root multiple signal classification (Root-MUSIC) has recently drawn a considerable attention, by using a polynomial rooting instead of spectral searching to reduce the complexity. The Root-MUSIC is computationally efficient in conjunction with a uniform linear array (ULA) composed of M sensors. Compared with traditional multiple signal classification (MUISC) algorithm, Root-MUSIC is more advantaged...
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