1,720,981 research outputs found
Innovative Application of the Born-Approximation for Analyzing Medium Motion Effects in Comsol Time Explicit Emw Module
No full textThis article presents an algorithm for integrating a previously developed methodology into the COMSOL Time Explicit EMW Module. The Born Approximations were applied to analyze medium motion effects, equivalent to weak bianisotropy. These effects are challenging to calculate precisely due to their low magnitude relative to computational noise in classical approaches. Integration into CAD enables broader and more effective application. Validation is provided for a 2.5 D problem of axial motion of a circular cylinder, demonstrating excellent agreement with the results
Microwave detection and dielectric characterization of cylindrical objects from amplitude-only data by means of neural networks
No full textAnalytical Evaluation of the Effects on the Electromagnetic Field Induced by a Moving Dielectric Slab
No full textA simple one-dimensional electromagnetic problem in the presence of moving objects is studied. The analytical solution is used to investigate the effects of motion on the electromagnetic field. The results show that for this class of one-dimensional problems the effects of motion are weaker than expected. For this reason the simple problem considered in this work could be of interest for investigating the reliability of inverse scattering procedures or for testing numerical methods
Performance of a causal anisotropic absorber for the truncation of finite element meshes in time domain electromagnetic unbounded problems
No full textRecent results on the existence, uniqueness and finite element approximation of the solution of time-harmonic electromagnetic boundary value problems
No full textThree-Dimensional Time-Harmonic Electromagnetic Scattering Problems from Bianisotropic Materials and Metamaterials: Reference Solutions Provided by Converging Finite Element Approximations
No full textA recently developed theory is applied to deduce the well posedness and the finite element approximability of time-harmonic electromagnetic scattering problems involving bianisotropic media in free-space or inside waveguides. In particular, three example problems are considered of which one deals with scattering from plasmonic gratings that exhibit bianisotropy while the other two deal with bianisotropic obstacles inside waveguides. The hypotheses that guarantee the reliability of the numerical results are verified, and the ranges of the constitutive parameters of the media involved for which the finite element solutions are guaranteed to be reliable are deduced. It is shown that, within these ranges, there can be significant bianisotropic effects for the practical media considered as examples. The ensured reliability of the obtained results can make them useful as benchmarks for other numerical approaches. To the best of our knowledge, no other tool can guarantee reliable solutions
Well Posedness and Finite Element Approximability of Three-Dimensional Time-Harmonic Electromagnetic Problems Involving Rotating Axisymmetric Objects
No full textA set of sufficient conditions for the well posedness and the convergence of the finite element approximation of three-dimensional time-harmonic electromagnetic boundary value problems involving non-conducting rotating objects with stationary boundaries or bianisotropic media is provided for the first time to the best of authors’ knowledge. It is shown that it is not difficult to check the validity of these conditions and that they hold true for broad classes of practically important problems which involve rotating or bianisotropic materials. All details of the applications of the theory are provided for electromagnetic problems involving rotating axisymmetric objects
Integrazione GA-FEM basata su una tecnica di calcolo distribuito per l'ottimizzazione di componenti passivi a microonde
No full textElectromagnetic inverse scattering of rotating axisymmetric objects
No full textThe electromagnetic inverse scattering problem for rotating axisymmetric objects is studied. A modification of a previously proposed two-step algorithm is adopted to obtain the first solutions to the problems of interest. In the first step, the forward solver is employed assuming zero rotating speed and the geometric and dielectric parameters are reconstructed by minimizing the cost function. In the second step, the values from the first step are used to determine the rotating speed. Numerical results for this type of inverse problems are provided for the first time by considering test cases with rotating homogeneous sphere and torus. The two-step algorithm is compared against the general inversion algorithm that relies on global optimization considering all unknown variables simultaneously. It is demonstrated that the proposed algorithm outperforms the general inversion procedure for all speeds of practical interest. The results are analyzed for noisy data in the near-field and far-field
Comparative results on the performances of finite element boundary truncation techniques in the time domain
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