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This paper shows that inverse scattering techniques can be successfully used to find the geometrical and constitutive parameters and the velocities of axially moving, inhomogeneous cylinders. For this reason, these techniques could be of interest in industrial applications or in plasma physics. In particular, the forward problem is solved by generalizing a semi-analytical recursive procedure developed...
This paper considers the electromagnetic scattering problem of a lamellar grating with period modulation, and presents a formulation based on the rigorous coupled-wave analysis (RCWA). The RCWA is originally developed to analyze the plane-wave scattering from perfectly periodic structures, and uses the pseudo-periodic property of the fields. Since the structure under consideration is not perfectly...
A strictly stated synthesis problem of inhomogeneous stationary and quasi-stationary impedance planes, which reflects a homogeneous plane wave in the given direction at the required polarization with a frequency shift, is solved. The impedance distribution law is obtained in the explicit form. Restrictions on class of realizable scattering patterns for passive impedance are formulated; formulas for...
In this work we provide a first result of reliability of the finite element method for time-harmonic electromagnetic problems involving moving objects with stationary boundaries. In addition, by considering a simple geometry allowing the computation of a semi-analytical solution, we will provide a first error analysis for finite element solutions and a comparison with the same type of result for problems...
In this work, we demonstrate theoretically and experimentally that a specific gradient-index meta-surface can convert a PW to a SW with nearly 100% efficiency. Distinct from conventional devices such as prism or grating couplers, the momentum mismatch between PW and SW is compensated by the reflection-phase gradient of the meta-surface, and a nearly perfect PW-SW conversion can happen for any incidence...
A particular goal of ultrasonic nondestructive testing comprises the identification of cracks, for instance, in welds. Set as an inverse scattering problem for elastic waves in solids it is essentially the crack tip scattering that delivers information about the crack size, which, on the other hand, is the crucial input for fracture mechanical life time estimation of the part under concern. Unfortunately,...
We deal with the scattering of a plane electromagnetic wave by a half plane with a sinusoidally deformed edge by a physical optics approximation. The normal incidence of a plane wave to the edge is assumed. A contribution of an edge to the field integral is asymptotically evaluated and basic properties of the edge scattering are clarified.
We present a novel multi-trace surface integral equation (SIE) method for solving multi-scale and complex electromagnetic problems. There are three major technical ingredients in the proposed SIE formulation: a. A discontinuous Galerkin integral equation method, which makes it possible to solve surface integral equations without any interelement continuity condition; b. A multi-trace surface integral...
Surface Integral Equations (SIEs) constitute a very powerful method for the analysis of electromagnetic scattering of homogeneous penetrable objects. The discretization of SIEs, however, results in a non-sparse system matrix, expensive to store and solve. In order to consider complex large-scale problems with a high number of unknowns, acceleration methods like the fast multipole method are required,...
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