Decoupling of antennas with wire metasurface structures: MRI applications

Metasurfaces are artificial two-dimensional structures with subwavelength periodicity. A shape and a size of the unit cells are responsible for electromagnetic properties of a metasurface. Metasurfaces provide specific boundary conditions which define the reflection and transmission properties with respect to incident plane waves. In the present work, we consider the structure based on the so-called mushroom-type metasurface having a high surface impedance in a certain frequency range. Such structures were previously employed in the microwave range to decouple closely spaced dipole antennas. Recently it was experimentally shown by the authors that such structures are also applicable to reduce mutual coupling between dipole elements of a body array coil for 7 Tesla MRI (operational frequency equal to 298 MHz). In this work, we extend our study in order to illustrate the effect of a mushroom structure on a radiofrequency field distribution inside an MR-scanner.