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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...

An explicit solution for the longitudinal and transverse polarizability of the symmetric dielectric intersecting double sphere is obtained as a rapidly converging series of integral operators, which is fast enough for real time calculation in Java Applet.

The electrostatic problem of two touching dielectric spheres in a uniform field is analyzed as an eigenfunction expansion in the tangent sphere frame. The spectrum of eigenfunctions is continuous; therefore, the scattered potential is expressed as a weighted integral of those eigenfunctions. It is shown that the weighting function satisfies a second-order ordinary differential equation, which contains only elementary functions. In particular, the longitudinal and transverse polarizabilities of the tangent sphere are being considered. We are also dealing with the plasmonic resonances (electrostatic resonances) that appear at the negative values of the permittivity ε. Some years ago Paley, Radchik, and Smith [A. V. Paley, A. V. Radchik, and G. B. Smith, J. Appl. Phys. 73, 3446 (1993)] claimed to have found an exact solution for the problem of two touching dielectric spheres in a uniform field. In light of the present study, it seems that their result is incorrect.

An explicit solution for the longitudinal and transverse polarizability of the asymmetric dielectric intersecting double sphere is obtained as a rapidly converging series of integral operators, which can be implemented efficiently, for example, in Java Applet. This article generalizes the results of the paper (Pitkonen M 2006 J. Math. Phys. 47 102901) to the asymmetric case and also allows the permittivities of the spheres to have different values.