Spinning thermal radiation is a unique phenomenon observed in condensed astronomical objects, including the Wolf-Rayet star EZ-CMa and red degenerate G99-47, due to existence of strong magnetic fields. Here, by designing symmetry-broken metasurfaces, we demonstrate that spinning with nonvanishing optical helicity can be realized even without applying field. We design engineering dispersionless band emits omnidirectional radiation, where our reaches 39% fundamental limit. Our results firmly...

This paper presents a novel zero voltage switch (ZVS) pulse-width modulation (PWM) DC/DC converter for high power, output applications. By using two active switches in the secondary side of transformer, proposed achieves not only ZVS entire load ranges but also soft commutation rectifier diodes. The topology has simple structure and control strategy. Simulation results experimental 2.8 kW 200 kHz are presented.

In this paper, an explicit and unconditionally stable finite-difference time-domain (FDTD) method is developed for electromagnetic analysis. Its time step not restricted by the space step, its accuracy ensured chosen based on accuracy. The strength of conventional FDTD thus preserved in avoiding a system matrix solution, while shortcoming eliminated step's dependence step. Numerical experiments both 2-D 3-D simulations have demonstrated performance proposed stability efficiency without sacrificing

In this paper, a fast explicit and unconditionally stable finite-difference time-domain (FDTD) method is developed, which does not require partial solution of global eigenvalue problem. method, patch-based single-grid representation the FDTD algorithm developed to facilitate both theoretical analysis efficient computation. This results in natural decomposition curl-curl operator into series rank-1 matrices, each corresponds one patch single grid. The relationship then theoretically analyzed...

An effective algorithm to construct perfectly matched layers (PMLs) for truncating time-domain finite-element meshes used in the simulation of three-dimensional (3-D) open-region electromagnetic scattering and radiation problems is presented. Both total- scattered-field formulations are described. The proposed based on solution vector wave equation an anisotropic dispersive medium. allows variation PML parameters within each element, which facilitates efficient use higher order basis...

Using an <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> matrix as the mathematical framework, we compactly represent a dense system by reduced set of parameters, thus enabling significant reduction in computational complexity. The error bound -matrix-based representation electrodynamic problem was derived. We show that exponential convergence with respect to number interpolation points...

The root cause of the instability is quantitatively identified for explicit time-domain finite-element method that employs a time step beyond allowed by stability criterion. With identification cause, an unconditionally stable successfully created, which and accurate solely determined accuracy regardless how large is. proposed retains strength in avoiding solving matrix equation while eliminating its shortcoming step. Numerical experiments have demonstrated superior performance computational...

We numerically demonstrate that a planar slab made of magnetic Weyl semimetal (a class topological materials) can emit high-purity circularly polarized (CP) thermal radiation over broad mid- and long-wave infrared wavelength range for significant portion its emission solid angle. This effect fundamentally arises from the strong gyrotropy or nonreciprocity these materials, which primarily depends on momentum separation between nodes in band structure. clarify dependence this underlying...

This paper presents a general approach for the stability analysis of time-domain finite-element method (TDFEM) electromagnetic simulations. Derived from discrete system analysis, determines by analyzing root-locus map characteristic equation and evaluating spectral radius finite element matrix. The is applicable to TDFEM simulation involving dispersive media various temporal discretization schemes such as central difference, forward backward Newmark methods. It shown that determined material...

A novel hybrid time-domain finite element-boundary integral method for analyzing three-dimensional (3-D) electromagnetic scattering phenomena is presented. The couples element and boundary field representations in a way that results sparse system matrix solutions are devoid of spurious modes. To accurately represent the unknown fields, scheme employs higher-order vector basis functions defined on curvilinear tetrahedral elements. handle problems involving electrically large objects,...

A general formulation is described for time-domain finite-element modeling of electromagnetic fields in a dispersive medium. The based on the second-order vector wave equation and incorporates dispersion effect medium via recursively evaluated convolution integral. This evaluation kept to second order accuracy using linear interpolation within each time step. Numerical examples are given validate proposed formulation.

State-of-the-art integral-equation-based solvers rely on techniques that can perform a dense matrix-vector multiplication in linear complexity. We introduce the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> matrix as mathematical framework to enable highly efficient computation of matrices. Under this framework, yet, no complexity has been established for inversion. In work, we...

To facilitate the broadband modeling of integrated electronic and photonic systems from static to electrodynamic frequencies, we propose an analytical approach study rank integral operator for electromagnetic analysis, which is valid arbitrarily shaped object with arbitrary electric size. With this approach, theoretically prove that a prescribed error bound, minimal interaction between two separated geometry blocks in operator, asymptotically, constant 1-D distributions source observation...

We develop a linear-complexity direct matrix solution for the surface integral equation (IE)-based impedance extraction of arbitrarily shaped 3-D nonideal conductors embedded in dielectric material. A inverse highly irregular system composed both dense and sparse blocks is obtained <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</i> ( xmlns:xlink="http://www.w3.org/1999/xlink">N</i> ) complexity with being size. It outperforms state-of-the-art...

The dense matrix resulting from an integral equation (IE)-based solution of Maxwell's equations can be compactly represented by H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -matrix. Given a general -matrix, prevailing fast direct solutions involve approximations whose accuracy only indirectly controlled. In this paper, we propose new algorithms is directly controlled, including both factorization and inversion, for solving...

An alternative method is developed to make an explicit FDTD unconditionally stable. In this method, given any time step, we find the modes that cannot be stably simulated by and deduct these directly from system matrix (discretized curl-curl operator) before marching. By doing so, original numerical adapted based on desired step rule out root cause of instability. The resultant marching absolutely stable for no matter how large it is, irrespective space step. accuracy also guaranteed chosen...

A time-domain, finite element-boundary integral (FE-BI) method is presented for analyzing electromagnetic (EM) scattering from two-dimensional (2-D) inhomogeneous objects. The scheme's finite-element component expands transverse fields in terms of a pair orthogonal vector basis functions and coupled to its boundary such way that the resultant element mass matrix diagonal, more importantly, delivers solutions are free spurious modes. integrals computed using multilevel plane-wave time-domain...

A high-capacity electromagnetic solution, layered finite element method, is proposed for high-frequency modeling of large-scale three-dimensional on-chip circuits. In this first, the matrix system original 3-D problem reduced to that 2-D layers. Second, layers further a single layer. Third, an algorithm logarithmic complexity speed up analysis. addition, excitation and extraction technique developed limit field unknowns needed final circuit layer only, as well keep right-hand side intact...

State-of-the-art integral-equation-based solvers rely on techniques that can perform a matrix-vector multiplication in O(N) complexity. In this work, fast inverse of linear complexity was developed to solve dense system equations directly for the capacitance extraction any arbitrary shaped 3D structure. The proposed direct solver has demonstrated clear advantages over state-of-the-art such as FastCap and HiCap; with CPU time modest memory consumption, without sacrificing accuracy. It...

It has been observed that finite element based solutions of full-wave Maxwell's equations break down at low frequencies. In this paper, we present a theoretically rigorous method to fundamentally eliminate the low-frequency breakdown problem. The key idea is original frequency-dependent deterministic problem can be rigorously solved from generalized eigenvalue frequency independent. addition, found zero eigenvalues cannot obtained as zeros because machine precision. We hence correct inexact...

Existing methods for solving the low-frequency breakdown problem associated with full-wave solvers rely on approximations, which has left a number of research questions to be answered. The conductors are also generally treated as perfect and dielectric loss is not considered. In this work, rigorous method that does utilize approximations developed eliminate low frequency finite-element based analysis general 3-D problems involving inhomogeneous lossless and/or lossy dielectrics nonideal...

A new first-principles-based volume integral equation (VIE) formulation is developed for the broadband full-wave extraction of general 3-D circuits, containing arbitrarily shaped lossy conductors with inhomogeneous dielectrics. The proposed accentuates all advantages VIE traditionally solving wave-related problems, while allowing multiport circuit parameters such as impedance Z-, admittance Y-, and scattering S-parameters at ports located anywhere in physical structure a circuit. Its without...

In this paper, we propose a fast <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -matrix-based direct solution with significantly reduced computational cost for an integral-equation-based capacitance extraction of large-scale 3-D interconnects in multiple dielectrics. We reduce the computation by simultaneously optimizing -matrix partition to minimize number matrix blocks and minimizing rank each block based on prescribed accuracy. With...