Analytical Model to Study the Electrostatic Resonance of Subwavelength Radially Inhomogeneous Negative Permittivity Spheres

This letter presents an analytical model to study the electrostatic scattering of subwavelength radially inhomogeneous spheres whose permittivity can be expressed as a general polynomial function of the radial distance r. This technique is particularly well suited to characterize the electrostatic resonance, also known as surface plasmon resonance, of radially inhomogeneous negative permittivity spheres.