Discretely Dielectric-Material Coated Dipole Antenna: Enhanced Tuning and Electric Field Reduction for Safety at 300 MHz

Motivation: Dipole antennas struggle with imaging small regions at 300 MHz due to their reliance on physical length for tuning, which limits resolution. Goal(s): This study aims to develop a discretely dielectric-material-coated (DDMC) dipole antenna for dipole-length-independent frequency tuning, improving imaging quality and safety. Approach: We designed and constructed discretely dielectric-material-coated dipole antenna and compared the DDMC design with fractionated dipole designs using simulations and bench-testing, employing a high-dielectric-material to achieve 300 MHz resonance without altering physical dimensions. Results: The DDMC dipole provided a more uniform B1+ distribution and lower electric fields, demonstrating superior decoupling and a higher Q-factor for enhanced ultra-high-field MRI performance. Impact: This research advances ultra-high-field MRI technology by enhancing imaging quality and safety through innovative dipole antenna designs. Future studies can explore optimized dielectric materials, improving access to high-resolution imaging in clinical settings and benefiting patients with complex anatomical needs.