Dielectric Constant Measurement Method for High Permittivity Metamaterial Design in MRI

Motivation: High permittivity metamaterials have shown benefits in UHF MRI. However, precise dielectric constant measurement method for metamaterials is in absence, which may lead to bias in field manipulation. Goal(s): Developing a precise measurement method to better mimicking dielectric materials’ role in field manipulation, where samples are placed at the reactive near-field region. Approach: A microstrip line resonator was used to measure resonances of metamaterials. The resonance of dielectric materials with particular properties were chosen as the reference. Their difference in resonance frequency is required to be minimized. Results: Metamaterials designed using our approach exhibited superior accuracy in mimicking the target dielectric pad. Impact: The proposed method leads to better mimicking dielectric materials’ role in field manipulation at reactive near region. Metamaterials designed with this method exhibit enhanced B1 field and lower SAR, signifying a significant advancement in UHF MRI and promising precise diagnoses.