Discrete Dielectric Coatings for Length Control and Tunability of Half-Wave Dipole Antennas at 300 MHz Magnetic Resonance Imaging Applications

TL;DR

This paper introduces a discretely dielectric-coated dipole antenna design that enhances frequency tuning, reduces SAR, and improves B1 field uniformity for UHF MRI, promising safer and more efficient imaging.

Contribution

The study presents a novel DDMC dipole antenna with discrete dielectric coatings that outperform traditional designs in UHF MRI applications.

Findings

Superior B1 field uniformity achieved

Significant SAR reduction demonstrated

Enhanced electromagnetic decoupling in arrays

Abstract

This study presents a novel discretely dielectric material-coated (DDMC) dipole antenna design for ultra-high-field (UHF) MRI applications. This design improves frequency tuning, lowers electric field intensity, and reduces SAR by including discrete high-permittivity dielectric coatings at both ends of the dipole. The DDMC dipole's performance was compared to that of a fractionated dipole design using metrics such as inter-element coupling, B1 field distribution, and SNR. Simulations and experimental results showed that the DDMC dipole provided superior B1 field uniformity with significantly reduced B1 variation along the dipole conductor while reducing SAR, making it a safer and more efficient option for MR signal excitation and reception in UHF MR imaging. Furthermore, with its improved electromagnetic decoupling performance, the multichannel array made from the proposed DDMC dipoles shows promise for improving parallel imaging and imaging quality in UHF MRI, with future work focusing on material optimization and scalability for multi-channel arrays.