Abstract-Numerical solution of electromagnetic scattering problems by the surface integral methods leads to numerical integration of singular integrals in the Method of Moments. The heavy numerical cost of a straightforward numerical treatment of these integrals can be avoided by a more efficient and accurate approach based on the singularity subtraction method. In the literature the information of the closed form integral formulae required by the singularity subtraction method is quite fragmented. In this paper we give a uniform presentation of the singularity subtraction method for planar surface elements with RWG,n×RWG, rooftop, andn×rooftop basis functions, the latter three cases being novel applications. We also discuss the hybrid use of these functions. The singularity subtraction formulas are derived recursively and can be used to subtract more than one term in the Taylor series of the Green's function.
The polarizability characteristics of nonspherical scatterers, especially cubes and squares, are studied in this paper. A surface integral equation for the electrostatic potential has been numerically solved for a cube and a square-shaped object. Nonuniform gridding of the dielectric object has been used to get a good accuracy in the solution. The results obtained for the polarizability of cubes using the surface integral equation are compared with those obtained from the volume integral equation and show a good agreement. We give simple approximation formulas for the polarizabilities as functions of the permittivity of the inclusions. The results give an improvement compared to earlier literature and also present a way to predict the effective properties of mixtures where cube-shaped inclusions are embedded in dielectric environment, which type of mixtures strongly generalize the effective-medium theories of the present literature.
An analytical boundary condition for modeling the electromagnetic properties of planar regular dense arrays of dipole particles for oblique incidence of plane waves is developed. The regular array is assumed to be dense which means that the dipole particles are close to each other. The interaction between the dipole particles is taken into account by interaction constant. The expression for the interaction constant is written in analytical form and is used for developing a transmission-line model for arrays of planar dipole scatterers. The regular dense array is modeled as a shunt impedance which is different for TM and TE polarizations. 1 Introduction 2 Theory 3 Imaginary Part of β 4 Impedance and Reflection Dyadic 5 Conclusion Appendix A. References
The classical soft-and-hard surface boundary conditions have previously been generalized to the form a • E = 0 and b • H = 0 where a and b are two complex vectors tangential to the boundary. A realization for such a boundary is studied in terms of a slab of special wave-guiding anisotropic material. It is shown that analytic expressions can be found for the material parameters and thickness of the slab as functions of the complex vectors a and b. Application of a generalized soft-and-hard boundary as a polarization transformer is studied in detail.
Ilari Hänninen, Mikko Pitkonen, Keijo I. Nikoskinen, and Jukka Sarvas, Method of moments analysis of the backscattering properties of a corrugated trihedral corner reflector, IEEE Transactions on Antennas and Propagation, Vol. 54, no. 4, pp. 1167-1173, 2006. © 2006 IEEEReprinted with permission.This material is posted here with permission of the IEEE. Such permission of the IEEE d oe s n ot i n an y w ay i m pl y I E E E e n d or s em en t of an y of Hel si n ki Un i v e r si ty of Technology's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org.By choosing to view this document, you agree to all provisions of the copyright laws protecting it.IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 54, NO. 4, APRIL 2006 1167 Method of Moments Analysis of the Backscattering Properties of a Corrugated Trihedral Corner ReflectorIlari Hänninen, Mikko Pitkonen, Keijo I. Nikoskinen, Senior Member, IEEE, and Jukka Sarvas, Member, IEEE Abstract-A method of moments (MoM) formulation is developed to analyze the backscattering properties of an anisotropic trihedral corner reflector, which is obtained by corrugating one or several of its interior faces. The proposed formulation treats the corrugated surface as ideally tuned to the incident wave frequency. The numerical analysis of the studied structures has been done using closed-form formulas and accurate numerical integration. The focus of the study reported in this paper has been the polarization responses of ideally tuned corrugated reflectors, which have interesting properties, particularly regarding elliptically or circularly polarized waves. We numerically verify that an appropriately corrugated reflector returns elliptically and circularly polarized waves with the same handedness as the incident wave. For a linearly polarized incident wave, the corner reflector is able to rotate them by 90 . Also the effect of the direction of the corrugation to the backscattering properties is studied. Index Terms-Corner reflector, electromagnetic scattering, method of moments (MoM), radar cross-section (RCS), soft and hard surface (SHS). I. INTRODUCTIONT RIHEDRAL corner reflectors are widely used as location markers and calibration targets in radar technology and remote sensing. They have a high backscattering radar cross-section over a wide angular range, they do not require any power to operate, they are mechanically easy to construct, and they can also be operated in difficult conditions. Conventional trihedral corner reflectors, i.e., reflectors made from a perfect electric conductor (PEC) material return linearly polarized incident electromagnetic waves with the same polarization but they reverse the handedness of elliptically and circularly polarized incident waves. Depolarizing trihedral corner reflectors, however, retain...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.