Innovative Coaxial Plane Synthesized Magnetic Focusing (SMF)

A new synthesized magnetic focusing (SMF) technology for multiple coaxial circular coils is proposed in this article. The fundamental principle of the proposed coaxial plane SMF is provided compared with previous SMF and transcranial magnetic stimulation (TMS) in medical applications. The proposed SMF theory determines the appropriate currents in multiple coaxial circular coils, resulting in a focused magnetic field distribution across a 3-D space. Simulation results show a $4.2\times $ sharper magnetic field with a cost of reduced peak magnetic field. Experiments for five coils with a 50-cm diameter at a focal distance of 10 cm show very good agreement with simulation. A single-source driver is first used replacing multiple drivers of conventional SMF.