A refined circuit model of high temperature superconducting spiral coils for MRI

A high temperature superconducting (HTS) spiral coil for magnetic resonance imaging (MRI) usually contains many turns of thin track patterned on an HT S film. The total length of the coil track is long (up to few meters) in or der to meet the requirement of fitting the resonance frequency to that of t he MRI scanner, in the range from 4MHz (0.1 T of magnetic fiend) to about 1 00 MHz thigh field). It takes too long time for commercially available soft ware to simulate such circuits because of the relatively large size and sma ll track width of the coil. A new computational frequency-domain model is d eveloped for design and analysis of HTS spiral surface coils for applicatio n to MRI, The model is faster in the simulation of the resonance frequencie s and s-parameters of the HTS spiral coils because some approximations are used for the coils with long track and low resonance frequency. The new mod el is based on the circuit analyses theory. The 2-inch coils were simulated for a field of 0.5 T, Tuning and matching are studied by using this model.