A stable discretization scheme is presented for the combined source integral equation (CSIE) of electromagnetic scattering from three-dimensional arbitrarily shaped homogeneous dielectric objects. ...The discretization scheme uses both the primary (Rao-Wilton-Glisson, RWG) and the dual (Buffa-Christiansen, BC) functions and avoids numerical problems that would appear if the equations were discretized with the RWG functions only.
A stable and efficient numerical scheme for the evaluation of surface integrals with 1/R3-type singularities is presented. The method is based on the combination of the direct evaluation method and ...the singularity subtraction technique. The proposed method allows robust numerical evaluation of integral operators containing hyper-singular double normal derivative kernels in the cases where the integral equations are discretized with Galerkin's type techniques.
The necessity of conforming testing procedures in developing accurate and reliable surface-integral-equation-based solvers for homogeneous penetrable objects is demonstrated. It is shown that only in ...Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) formulation with a conforming testing procedure, the interface conditions become properly tested for both the tangential and normal field components. Numerical experiments illustrate that the use of a nonconforming testing procedure can lead to a significant decrease on the solution accuracy or erroneous diverging results.
Calderon preconditioning is a recently proposed technique for improving conditioning of ill-conditioned matrices arising from discretization of surface integral equations. In electromagnetics the ...method has been developed for both perfectly conducting and homogeneous penetrable objects. In the case of penetrable objects the large variety of possible material parameters poses additional challenges on the efficiency of the preconditioner. We demonstrate with numerical experiments that problems may appear in particular at high material parameter values, at the physical resonances of the object, and at negative or zero material parameters. As realistic examples of objects with zero or negative material parameters we consider plasmonic nanoparticles at optical wavelengths.
A numerical approach based on the surface integral equation (SIE) method is developed for the analysis of time-harmonic electromagnetic scattering by impenetrable objects equipped with mixed ...impedance boundary conditions (MIBCs). MIBC is an axially anisotropic generalization of the conventional isotropic (Leontovich) impedance boundary condition. The developed SIE formulation utilizes surface Helmholtz decomposition, the self-dual formulation of Yan and Jin, and loop and star RWG functions. A combined field formulation is applied to avoid internal resonances.
Solving IBC-CFIE With Dual Basis Functions Ylä-Oijala, Pasi; Kiminki, Sami P; Järvenpää, Seppo
IEEE transactions on antennas and propagation,
12/2010, Letnik:
58, Številka:
12
Journal Article
Recenzirano
The surface integral equation method is applied to solve electromagnetic scattering by arbitrarily shaped three-dimensional imperfectly conducting objects modeled with the Leontovitch impedance ...boundary condition (IBC). Dual basis functions are used to remove previously reported difficulties associated with the solution of the combined field integral equation for objects with the IBC. By expanding the magnetic current with quasi-curl conforming dual functions and the electric current with divergence conforming primary (RWG) functions leads to a stable discretization procedure for the rotation (n ×) operator required by the IBC.
After the first detection of its binary nature, the spectroscopic monitoring of the non-thermal radio emitter Cyg OB2 No. 9 (P = 2.4 yr) has continued, doubling the number of available spectra of the ...star. Since the discovery paper of 2008, a second periastron passage has occurred in 2009 February. Using a variety of techniques, the radial velocities could be estimated and a first, preliminary orbital solution was derived from the He I 5876 line. The mass ratio appears close to unity and the eccentricity is large, i.e., 0.7-0.75. X-ray data from 2004 and 2007 are also analyzed in quest of peculiarities linked to binarity. The observations reveal neither large overluminosity nor strong hardness, but it must be noted that the high-energy data were taken after the periastron passage, at a time where colliding wind emission may be low. Some unusual X-ray variability is however detected, with a 10% flux decrease between 2004 and 2007. To clarify their origin and find a more obvious signature of the wind-wind collision, additional data, taken at periastron and close to it, are needed. Based on observations collected at the Haute-Provence Observatory and with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).
A Calderon preconditioned (CP) surface integral equation method is developed for the analysis of scattering by piecewise homogeneous dielectric and composite metallic and dielectric objects. The ...method is based on the electric current formulation (ECF), which only uses the electric surface currents as unknowns. In the ECF the ill-conditioned electric field integral operator and the well-conditioned magnetic field integral operator appear on separate equations, making the application of the CP much easier than e.g., in the PMCHWT formulation where these operators are mixed. In particular, using ECF, Calderon multiplicative preconditioner (CMP) can be straightforwardly extended for composite objects with junctions. Numerical examples demonstrate that the developed formulation, CMP-ECF, is well-conditioned on a very broad frequency range.
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