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The T-matrix is a powerful tool that provides the complete description of the linear interaction between the electromagnetic field and a given object. In here, we generalize the usual monochromatic formalism to the case of polychromatic field-matter interaction. The group of transformations of special relativity provides the guidance for building the new formalism, which is inherently polychromatic. The polychromatic T-matrix affords the direct treatment of the interaction of electromagnetic pulses with objects, even when the objects move at constant relativistic speeds. • We expand the T-matrix method to the domain of polychromatic fields. • We put the T-matrix method in the framework of representations of the Poincare group. • We derive the matrix element of the Lorentz boost for the T-matrix in closed form. [ABSTRACT FROM AUTHOR]

The interaction of a stratified cylinder with an elliptically inhomogeneous plane wave is introduced and also determined through a rigorous theoretical approach. The scattered electromagnetic field by a multilayered cylinder is investigated through an application of the generalized Vector Cylinder Harmonics (VCH) expansion. The exact mathematical model to represent this scenario considers the so-called complex-angle formalism reaching a superposition of Vectorial Cylindrical-Harmonics and the T-matrix formulation to contemplate the multi-scattering process between the cylinders. The validation of the procedure was accomplished with a comparison between the numerical results obtained with the Finite Element Method (FEM) in Comsol Multiphysics environment and a homemade Matlab code. [ABSTRACT FROM AUTHOR]

Highlights • The spheroidal beam shape coefficients are investigated by using an intrinsic method, for the case of general oblique illumination. • The analytic solution is constructed within the framework of the GLMT. • Numerical results concerning beam shape coefficients in spheroidal coordinates are presented. Abstract When dealing with T-matrix scattering, e.g. in the framework of Generalized Lorenz-Mie Theory (GLMT) or of Extended Boundary Condition Method (EBCM), the incident electromagnetic fields are expanded over a set of vectorial wave functions, with expansion coefficients expressed in terms of beam shape coefficients (BSCs). In the case of structured beams, the evaluation of these BSCs may constitute a challenging issue, particularly in the case of spheroidal coordinates. BSCs in spheroidal coordinates have been originally evaluated using an extrinsic method, i.e. they have been expressed in terms of more conventional BSCs in spherical coordinates. Later on, it has been possible to provide expressions to evaluate spheroidal BSCs using an intrinsic approach, i.e. by working only inside the spheroidal coordinate system used to deal with the scattering problem. Fairly recently, the intrinsic method for the evaluation of BSCs in spheroidal coordinates for on-axis standard configuration has been released in the archival literature. The present paper extends the intrinsic method to the case of oblique illumination. It also serves as a review devoted to GLMTs in spheroidal coordinates. [ABSTRACT FROM AUTHOR]

A full computer-based methodology is proposed for electromagnetic transient simulations in power cables characterized by an arbitrary cross-section geometry. The frequency-dependent parameters of the cables are calculated using finite element method, and the three-phase cable modeling is carried out using modal decoupling and fitting techniques. The multiconductor representation of a sector-shaped cable is possible from the calculation of a constant and real modal transformation matrix, resulting four independent propagation modes (three phases and cable shield), which are modeled from the inclusion of frequency effect in the classic Bergeron method. The currents and voltages are expressed as a system of differential equations, which are presented as state equations and solved using numerical integration methods. The proposed modeling technique allows the inclusion of time-variable and nonlinear elements during electromagnetic transient simulations in the time domain, which is not possible from frequency-domain models that are solved using inverse transforms. The proposed model is validated from results simulated using numerical Laplace transform and exact modal transformation matrix for calculation of phase currents and voltages. [ABSTRACT FROM AUTHOR]

Abstract: Using the T-matrix approach electromagnetic scattering by a non-axisymmetric particle with an arbitrary permittivity tensor is studied. The electromagnetic fields inside the scatterer are expressed by a system of quasi-spherical vector wave functions which are derived by the use of inverse Fourier transform. Using this expansion a solution of the light scattering problem in the framework of the null-field method is obtained. The implemented T-matrix program is parallelized using both OpenMP and MPI parallel paradigms. Numerical scattering results for anisotropic ellipsoids are presented. [Copyright &y& Elsevier]

A time-domain distortion characterization of electromagnetic-field sensors is performed using Hermite–Gauss functions. For every electromagnetic-field sensor, a transformation matrix is calculated in the spanned Hermite–Gauss signal subspace. The calculated matrix is then compared to a reference transformation matrix to give a measure of distortion. Distortion characteristics for different frequency ranges are calculated to obtain a spectral interpretation. Unique properties of Hermite–Gauss functions under the Fourier transform are used to calculate the distortion characteristics from a single set of time-domain measurements. Distortion characteristics of an asymptotic conical dipole are compared to three wire monopoles of different lengths. A time-domain simulation based on solving an electric-field integral equation using the method of moments is performed. Distortion characteristics resulted from the simulation and those obtained using measurement data are compared to each other. Finally, the sensitivity of the sensors is taken into account in the distortion analysis. [ABSTRACT FROM PUBLISHER]

Abstract: Using the T-matrix approach electromagnetic scattering by a biaxial anisotropic non-axisymmetric particle is studied. Electromagnetic fields inside the scatterer are expressed by a system of quasi-spherical vector wave functions which are derived by use of inverse Fourier transform. Using this expansion a solution of the light scattering problem in the framework of the null-field method with discrete sources is obtained. Numerical scattering results for ellipsoids and cubes are presented. For validation the calculation results obtained are compared with results from other light scattering programs such as DDSCAT and ADDA. [Copyright &y& Elsevier]

Utilizes the T-matrix theory to analyze the electromagnetic far field, as well as the near field, originating from light interaction with a red blood cell volume-equivalent spheroid. Methods used to measure blood; What studies conducted indicate; Information on the T-matrix theory.