A Design Methodology for Response-controlled Passive Magnetic Metasurfaces

In this paper, we introduce a design methodology for response-controlled passive magnetic metasurfaces excited by an active RF coil placed in its near-field region. Starting from conceiving the geometrical parameters of the radiating system, we first create the mask reporting the desired magnetic field distribution to be achieved at a certain plane. After that, the currents, in amplitude and phase, producing the desired field distribution, are evaluated. This step is carried out through an optimization algorithm, based on a magneto-static hypothesis. Then, we determine the capacitive loads required to achieve such behavior, exploiting a single full-wave simulation. Finally, numerical simulations of the overall designed radiating system are performed to validate the obtained results. The possibility to rapidly design and configure a passive metasurface, able to show the desired magnetic field distribution, can be a valuable tool in different applications, like magnetic resonance imaging and wireless power transfer.