Wave-impedance-match materials for Travelling Wave MRI

Motivation: Wave-impedance-match is key to ensure maximized power transmission in travelling-wave (TW) MRI. Currently, only coaxial waveguide method has been proposed. It requires adding metallic cylinder inside magnet and gradient coils, which introduces risks of mechanical instability and patient safety due to eddy current. Goal(s): Propose a novel wave-impedance-match method for TW excitation with non-metallic materials. Approach: Dielectric cubes made up of easy-accessible distilled water were modelled and placed between feed and the load. Power-flow-density and power-loss results were used to evaluate wave-impedance-match. Results: Wave-impedance-match varies with length and width of dielectric cube. The well-matched conditions with dielectric cube and coaxial waveguide are similar. Impact: Non-metallic wave-impedance-match method was proposed for TW excitation. This has the potential to accelerate maturity of traveling-wave excitation method in UHF MRI.