COMPUTATION OF MULTIPOLE MOMENTS FOR SHORT THIN WIRE CHIRAL STRUCTURES

Abstract

This paper considers the computation of the multipole moments of small chiral wire structures. The multipole moments are reviewed and it is shown that the charge induced on the wire must be accurately computed. A quasistatic thin-wire Galerkin Method of Moments formulation has been developed to numerically compute the charge distribution. The chiral structures under consideration are on the borderline of "thin" and a Body of Revolution Method of Moments formulation has also been developed for use as a check on the accuracy of the thin-wire approximations. It is shown that the "standard" thin-wire formulation is not sufficiently accurate, but the relatively simple addition of an end-cap greatly improves the convergence and accuracy of the formulation with acceptable computation cost. Finally, the formulation is extended to include bent wires, permitting the electric and magnetic dipole moments as well as the electric quadrupole moment to be calculated for a small chiral structure. [Vol. 10, No. 3 (1995), Special Issue on Advances in the Application of Method of Moments to Electromagnetic Radiation and Scattering Problems, pp 129-138]