State–Space Formulation of Scattering with Application to Spherically Symmetrical Objects

Abstract

A new differential formulation of scattering from dielectric bodies is described. The problem is reduced to the solution of spatially varying state–space equations for the multipole coefficients of the scattered field. The equations are confined into the body, and the solution yields directly the scattering coefficient outside the body. The method is applied to spherically symmetrical objects. Numerical results are presented for plane wave scattering from Luneberg and Eaton lenses and a plasma-coated conducting sphere. The radiation properties of an electric and magnetic dipole antenna, respectively covered by a plasma and a dielectric layer, are studied. The numerical results show that the radiation of these antennas can be enhanced over the free-space radiation by adjusting the thickness and the density of the layer.

Radiation from a spherical antenna covered by an inhomogeneous over-dense plasma layer

“…When the spherical antenna is coated by an inhomogeneous plasma layer, the scattering occurs both from the conducting sphere and the plasma layer. This problem can be solved exactly by the state-space method by modifying the boundary conditions, as was done in the case of a plane-wave scattering from a dielectric-coated conducting sphere (Hizal and Tosun 1973).…”

“…Ao are the scattering coefficients of the plasma layer, in the presence of the conducting sphere, for respectively outgoing and ingoing scattered radiations; and ak0 (xz) and ato (XI) are the scattering coefficients respectively for the exterior (r 2 rz) and interior (r I rl) regions. The scattering matrices can be written in the following form (Hizal and Tosun 1973):…”

“…This effect may be used for overcoming the block-out of radiation from an antenna on a re-entry vehicle due to the surrounding ionization. Radiation can be enhanced also from other antennae, such as electrical dipoles covered by plasma layers (Yip 1972, Hizal andTosun 1973).…”

“…Several techniques may be applied, for instance those of Shafai (1972) and Yeh and Wang (1972). In this paper we solve this problem by the state-space method (Hizal and Tosun 1973), and present some new numerical results.…”

State‐space formulation of two‐dimensional electromagnetic scattering from dielectric cylinders

“…The method of solution presented here may be called the state-space method because of its similarity to a more general three-dimensional vector scattering problem [Hizal and Tosun, 1973]. It is essentially a polarization-source formulation [Bates, 1972] in which the volume induction theorem is the starting point.…”