A 40-mm High-Temperature Superconducting Surface Resonator in a 3-T MRI System: Simulations and Measurements

In this paper, the Ansoft high-frequency structure simulation (HFSS) was adapted to investigate the unloaded quality-factor value of the radio-frequency (RF) receiving resonator. This paper focused on the materials aspects, and a comparison between electromagnetic stimulations and measurement was conducted. A 40 mm in diameter Bi₂Sr₂Ca₂Cu₃O_x (Bi-2223) tape high-T_c superconducting RF resonator in 3 T was stimulated and built. The simulation models were established according to the experimental dimension of the Bi-2223 surface resonator. Measurements show that the Bi-2223 surface resonator at 77 K provides a gain of 3.84-fold signal-to-noise ratio on phantom images over that of the homemade copper resonator at 300 K. Measuring results were in accordance with predicted ones, and the difference between the predicted SNR gains and measured SNR gains is 1%. This paper suggests that using a Bi-2223 surface resonator at 77 K could be more useful for magnetic resonance imaging coils than a copper surface resonator at 300 K.