Artificial dielectric waveguide for efficient traveling-wave MRI at 7T

Motivation: Although dielectric waveguides can facilitate efficient travelling-wave MRI, their effectiveness is constrained by the availability of high-permittivity materials. Goal(s): Design dielectric waveguide with artificial dielectric slabs for efficient travelling-wave MRI at 7T. Approach: Artificial dielectric slabs with high in-plane permittivity were employed, consisting of periodic metal patches on alternating and shifted layers. Results: Compared to previously reported dielectric waveguides, the artificial dielectric waveguide demonstrates comparable efficacy in TE11-TM11 mode-conversion, power-focusing, and phase-velocity matching. These findings have been validated through numerical simulations and MRI studies conducted on a saline head phantom. Impact: The promising results offer valuable insights into the design of future UHF MRI travelling-wave transmission systems.