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Title: Electrodynamics of a ring-shaped spiral resonator

We present analytical, numerical, and experimental investigations of electromagnetic resonant modes of a compact monofilar Archimedean spiral resonator shaped in a ring, with no central part. Planar spiral resonators are interesting as components of metamaterials for their compact deep-subwavelength size. Such resonators couple primarily to the magnetic field component of the incident electromagnetic wave, offering properties suitable for magnetic meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow the sequence of the odd numbers as f{sub 1}:f{sub 2}:f{sub 3}:f{sub 4}… = 1:3:5:7…, despite the nearly identical boundary conditions for electromagnetic fields at the extremities of the resonator. In order to explain the observed spectrum of resonant modes, we show that the current distribution inside the spiral satisfies a particular Carleman type singular integral equation. By solving this equation, we obtain a set of resonant frequencies. The analytically calculated resonance frequencies and the current distributions are in good agreement with experimental data and the results of numerical simulations. By using low-temperature laser scanning microscopy of a superconducting spiral resonator, we compare the experimentally visualized ac current distributions over the spiral with the calculated ones. Theory and experiment agree well with each other. Our analytical model allows for calculation of a detailed three-dimensionalmore » magnetic field structure of the resonators.« less
Authors:
; ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [5]
  1. Laboratory of Superconducting Metamaterials, National University of Science and Technology “MISIS,” Moscow 119049 (Russian Federation)
  2. (Germany)
  3. B. Verkin Institute of Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Kharkov 61103 (Ukraine)
  4. Physikalisches Institut, Karlsruhe Institute of Technology (KIT), Karlsruhe 76131 (Germany)
  5. (KIT), Karlsruhe 76131 (Germany)
Publication Date:
OSTI Identifier:
22278072
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOUNDARY CONDITIONS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; ELECTRIC CURRENTS; ELECTRODYNAMICS; ELECTROMAGNETIC FIELDS; ELECTROMAGNETIC RADIATION; INTEGRAL EQUATIONS; MAGNETIC FIELDS; MICROSCOPY; SUPERCONDUCTING CAVITY RESONATORS; THREE-DIMENSIONAL CALCULATIONS