Evaluation of Coaxial Dipole Antennas as Transceiver Elements of Human Head Array for Ultra-High Field MRI at 9.4T

Arrays of dipole antennas were recently introduced as transceiver RF coils for human head imaging at UHF as a simple and robust alternative to loop arrays. Due to the head size, dipoles should be significantly shorter than λ/2 at working frequency. Short dipoles suffer from high SAR and insufficient brain coverage. In addition, since head arrays are usually placed on rigid holders, the resonance frequency of dipoles change drastically with head size variation. In this work, we developed a coaxial dipole array for human head imaging at 9.4T. The developed coil provides whole-brain coverage, low SAR, and low frequency variation.