Slotted Coaxial Cavity Resonator for Head Imaging at Ultra High Fields

Anna Andreychenko¹, Alexander J.E. Raaijmakers¹, Peter R. Luijten¹, Jan J.W. Lagendijk¹, Cornelis A.T. van den Berg¹

Waveguide slot antennas are popular directional antennas used in microwave engineering at UHF (>300 MHz). The operational RF frequency of ultra high field MRI falls into this frequency range. A slotted coaxial cavity resonator with eight independent ports has been designed for human head imaging at 11.7 T. Based on the FDTD simulations, the resonator showed 13 % higher B1+ efficiency than the conventional birdcage head coil when the quadrature phase settings were applied. The presence of eight ports was exploited for effective RF shimming. This design can be a cheap and easily manufactured alternative to the existing coil designs for ultra high field head MRI.