Superconductive ultra-compact resonator with double-spiral structure
We describe a practical design of an ultra-compact double-spiral superconductive Nb micro-resonator as a potential magnetic element of RF metamaterial. This resonator consists of two superconducting Nb spirals, sandwiched face to face, with a small gap filled with dielectric. We study the resonator spectral response and its inner modes using numerical simulation in HFSS. In experiment with a Laser Scanning Microscope (LSM) we confirm the predictions for the resonance frequencies of Nb superconductive resonator and its inner modes structure. The achieved resonator size with respect to the wavelength in our experiment is about {\lambda}/4200. Small size and the ease of manufacturing make the double-spiral resonator an attractive solution for superconductive filters, coupling circuits, and for magnetic component of a metamaterial.