Achieving sub-wavelength resonant structures and transparency by a conducting spheroid with metamaterial coatings

Abstract

The possibility of using metamaterial covers to dramatically enhance the total scattering cross-sections (SCS) or drastically reduce total SCSs of spheroidal objects is presented. The scattering problem by a conducting spheroid with metamaterial coating at axial incidence is studied using an analytic solution by expanding the incident and scattered waves in terms of spheroidal vector wave functions and imposing the appropriate boundary conditions at each spheroidal surface. Numerical results show that the total SCSs of a conducting spheroid with different metamaterial coatings can be dramatically enhanced to achieve ‘sub-wavelength resonant structures’ or drastically reduced to achieve ‘transparency’ of objects. The results with different parameters, such as relative permittivity, the spheroidal geometry, and the ratio of semimajor axes of two layers, are provided and discussed.