A Noninvasive Field-Enhanced Magnetic Stimulator Using Secondary Ferrite Core and Resonant Structure

The secondary ferrite core and resonant structure is proposed to enhance the field strength for the noninvasive magnetic stimulator. The tissue is placed between double square source coils and the secondary ferrite core. Resonant coils are added to aid in modulating the electric field. The field distribution simulations are conducted and the ex-vivo measurements are carried out. The experimental setup is compared to a conventional design where the secondary ferrite core is absent. Through experiments, it is found that when the ferrite core is applied at the source frequency of 450 kHz, the induced electric field could be increased by 1.22 times.