Control of the near magnetic field pattern uniformity inside metamaterial-inspired volumetric resonators

In recent years metamaterial-inspired resonators, due to the ability to form desired near field patterns at subwavelength scale, have found application in various practical fields, i.e., magnetic resonance imaging or wireless power transfer. This paper proposes an approach for controlling the near electromagnetic field distribution inside the volumetric metamaterial-inspired structure based on a set of split-ring resonators or materials with high permittivity. We numerically and experimentally demonstrate how to precisely manipulate the near-field pattern’s uniformity by changing the number of resonant elements while maintaining the geometric dimensions of the structure. The effectiveness of the concept was also verified via a magnetic resonance imaging study. The optimized volumetric metamaterial-inspired resonator showed an increase in transmit efficiency and receive performance of the large body coil compared to the commercial dedicated radiofrequency coil. • The idea of near magnetic field control in metamaterial-inspired volumetric resonators. • The possibility of increasing the magnetic field uniformity in the volume of interest. • Improvement of transmit efficiency and receive sensitivity in 1.5 T MRI.