Measurements of Dispersive and Complex Permittivity Using a Deep-Subwavelength Plasmonic Skyrmion Resonator

A novel method is proposed to measure dispersion and complex permittivity using densely and equally spaced skyrmion modes in a deep-subwavelength spoof localized surface plasmon (SLSP) resonator. The SLSP resonator is ultra-compact, with an electrical size of λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>/89 or λg/27 (λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space w