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We consider meta-surfaces based on two dimensional arrays of nano-particles or surface-interruptions. Two types of novel inclusions are discussed. The first are non-reciprocal plasmonic nano-ellipsoids exposed to a bias magnetic field, arranged to create a meta-surface supporting two-type rotations (electromagnetic and geometric) and exhibit strong non-reciprocity. The second are local interruptions...
Image restoration issues are closely connected with imaging systems, where image resolution is limited by diffraction phenomenon. The presented work is motivated by the super acuity of the Human vision, where the restoration step is implemented by some kind of parallel processor unit — neural network. The de-convolution process is formulated as a machine learning problem and the inverse operator is...
Future Cosmic Microwave Background polarisation experiments will require large detector arrays to achieve the required sensitivity for precise measurements. New cost- and time-effective techniques are required for mass production of high performance passive components. We present electromagnetic test results on an assembly of feed horn and OMT prototypes, operating in the W-band and fabricated by...
A full-wave hybrid formulation is proposed for the efficient and accurate modeling of substrate integrated waveguides by rigorously accounting for all possible interactions among elements such as vertical metallic or dielectric posts and coupling or radiating slots. The method is specifically accelerated in order to maximize the efficiency of the analysis of common structures. Its flexibility allows...
In this paper, we present a modeling methodology for the prediction of the magnetic shielding effectiveness in the near field at low frequencies. This study shows an analytical method which is based on magnetic moments approximations to predict the shield effectiveness for infinite plane with narrow slot. The results obtained with the proposed method are compared with the numerical results.
An in-depth analysis of the electromagnetic interferences generated by trains requires a better understanding of specific railway interference sources. Interferences due to the losses of contact between catenary and pantograph are among them This paper presents a modeling methodology proposed to analyze the effect of pantograph arcing on GSM-R antennas located on the train roof. The model was developed...
This paper expands previous work on 1-D capacitor-connected grids by exploring a 2-D CCG case. The fractional bandwidth achieved by a 2-D CCG with 1μF coupling capacitance largely exceeds the bandwidth limitation of conventional 2-D MIWs. Compared to a conventional 2-D MIW, 2-D CCG waveguide surfaces are less dispersive over a greater bandwidth. 2-D CCG offers great potential to be used as UWB contactless...
Efficient algorithms are proposed for power balance calculations in the case of lossy composite metallic and dielectric structures, when they are analyzed by using method of moments (MoM) applied to surface integral equations (SIEs). In particular, the algorithms are applied in the case when Galerkin variant of MoM is used to solve electric field integral equation (EFIE) in combination with PMCHWT...
The multiple scattering by finite parallel perfect electric conducting (PEC) circular cylinders is considered. The problem is solved by the method of moments (MoM). The unkown current density on each cylinder is expanded with global basis functions and the Galerkin's method is used to obtain a matrix equation. Analytical expressions are obtained for the matrix elements by using Graf's addition theorem...
We revisit the formulation within the FDTD method of the Abraham-Lorentz model of a 1-electron atom coupling to an external electromagnetic field via the dipole interaction between the field and the moving charge. This classical problem is reformulated for a purely discrete space in discrete-time by specifying the electromagnetic potentials and the electron charge density only at discrete spatial...
This paper introduces a Boundary Element reconstruction method to predict the electromagnetic fields generated by unknown sources. This procedure allows to calculate the field distributions in free space directly from a limited number of measurements carried out on a closed surface which contains all the radiating sources. The accuracy of the proposed procedure has been found to be satisfactory through...
This contribution presents a domain-decomposition preconditioner that achieves higher rates of convergence than comparable methods and is yet simple to implement. Its numerical properties are illustrated by examining the eigenvalue distribution of the preconditioned finite element matrix. The practical usefulness of the proposed method is demonstrated by reference to a large-scale antenna array.
This paper describes the network oriented modeling procedure for multiport microwave structures. The various approaches to the equivalent network synthesis of multiport microwave structure are discussed. For the estimation of the system's poles and zeros positions, the matrix system identification procedure in conjunction with the model order selection algorithm are introduced.
Chemical sensing is one of the most promising applications of graphene based nanostructures. Here, we present a study of the effects of lithium adsorption on the electronic properties of graphene derivatives and its ability to serve as a chemical linker for different organic molecules. Lithium adsorption is found to significantly decrease the bandgap of armchair graphene nanoribbons (AGNRs), turning...
A finite element boundary integral approach with the Green's function of the rectangular cavity is introduced and applied to the simulation of reverberation chambers. In contrast to all other approaches that use the cavity Green's function, the computationally expensive part of the system matrix is factorized in the spectral domain yielding a significant acceleration of the algorithm. Numerical results...
This paper presents a novel methodology to characterize the DVB-T2 MISO vs SISO performance using field test measurements. The proposed methodology uses general purpose digital vector signal analyzers to record the required DVB-T2 MISO/SISO IQ (In-phase and in-quadrature) signals in the coverage area to be later processed using a laboratory play out system with a software based custom DVB-T2 receiver...
The response of a continuously layered medium to a pulsed source is evaluated by using the classical Sommerfeld-Weyl spectral representation. A contrast-source integral equation for the time-normalized wavenumber spectral constituent is derived. For certain values of the normalized wavenumber, this equation cannot be solved by a stable time-domain algorithm. The instabilities correspond to the occurrence...
Temporal discretization has a profound influence on the stability of numerical methods for the solution of time domain integral equations. Though many methods have been proposed, current successful methods can be grouped into two categories: Galerkin methods, and finite difference delay modeling (FDDM) methods. As in many cases where competing methods coexist, each method has advantages and drawbacks...
This work provides the experimental validation of a near field — far field (NF-FF) transformation technique with spherical scanning for electrically long antennas, which requires a nonredundant number of NF data. Such a technique is based on the nonredundant sampling representations of the electromagnetic fields and uses a prolate ellipsoid to shape an elongated antenna. A two-dimensional optimal...
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