Auxetics-Inspired Tunable Metamaterials for Magnetic Resonance Imaging

Area of Science:

• Materials Science
• Metamaterials
• Negative Poisson's Ratio Structures

Background:

• Auxetic materials exhibit counterintuitive deformation with a negative Poisson's ratio.
• Metamaterials offer unique electromagnetic properties, but achieving mechanical tunability for applications like MRI remains a challenge.

Purpose of the Study:

• To design and fabricate mechanically tunable auxetic metamaterials for megahertz (MHz) frequency applications.
• To optimize these metamaterials for enhanced performance in magnetic resonance imaging (MRI).

Main Methods:

• Exploiting auxetic structures with metallic helices to create tunable metamaterials in planar and hemispherical configurations.
• Utilizing 3D printing technology for fabrication.
• Investigating frequency tunability through mechanical deformation and modified electromagnetic interactions.

Main Results:

• Achieved a tunable metamaterial with a negative Poisson's ratio.
• Demonstrated an ≈20 MHz frequency shift during deformation.
• Experimental validation in a 3.0 T MRI system showed a ≈4.5× increase in signal-to-noise ratio.

Conclusions:

• The developed auxetic metamaterials offer a novel, tunable platform for MRI.
• These materials significantly boost MRI performance, paving the way for practical metamaterial integration in medical imaging and other fields.