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Abstract

The characteristics and performance of a novel type of high-Tc superconducting resonator, consisting of two superconducting spirals separated by a low-loss dielectric, have been observed. Experimentally two square spirals of linewidth 50 pm were patterned out of thin films of YBCO and tested in the temperature range 77-90 K. Resonators made from 25-30 turn spirals, which were separated by a 0.0005" teflon sheet, had frequencies in the range 30-60 MHz, and the maximum Q observed was 32,000 at 77 K. An iterative algorithm has been developed to predict the frequency and the fields for the general case where the resonator consists of two arbitrarily shaped spirals, and the spirals are identical except that they are wound in opposite senses about their common axis. The algorithm has been implemented for a 10-turn square spiral with dimensions similar to the experimental thin film resonators, using finite element methods to model the electric and magnetic fields.