Theory of spoof magnetic localized surface plasmons beyond effective medium approximations

A homogeneous negative permeability sphere can support magnetic localized surface plasmons (MLSPs). Generally, materials are metamaterial (MM) structures exhibiting very deep subwavelength spatial scales, whose effects may be detrimental in the near-field for those applications based on effective medium approximations. We suggest to overcome this fundamental limitation by demonstrating analytically that electromagnetic distribution, associated a MLSP resonance and excited source, accurately reproduced outside substituting with high-index dielectric one same radius. Considering large class of ferroelectric shows ultra-high constant low-losses at low frequency (up GHz), our spoof MLSPs theory could key tool realizing high performance photonic devices radiofrequency microwave regions.