A Noninvasive Magnetic Stimulator Utilizing Secondary Ferrite Cores and Resonant Structures for Field Enhancement

TL;DR

This study introduces a noninvasive magnetic stimulator design using ferrite cores and resonant structures, significantly enhancing electric field induction in tissue for potential medical applications.

Contribution

The paper presents a novel noninvasive magnetic stimulation method employing secondary ferrite cores and resonant coils, achieving a 122% increase in electric field strength compared to traditional designs.

Findings

Electric field increased by 122% with ferrite cores at 450 kHz

Field distribution was localized and verified experimentally

Simulation results matched ex-vivo measurements

Abstract

In this paper, secondary ferrite cores and resonant structures have been used for field enhancement. The tissue was placed between the double square source coil and the secondary ferrite core. Resonant coils were added which aided in modulating the electric field in the tissue. The field distribution in the tissue was measured using electromagnetic simulations and ex-vivo measurements with tissue. Calculations involve the use of finite element analysis (Ansoft HFSS) to represent the electrical properties of the physical structure. The setup was compared to a conventional design in which the secondary ferrite cores were absent. It was found that the induced electric field could be increased by 122%, when ferrite cores were placed below the tissue at 450 kHz source frequency. The induced electric field was found to be localized in the tissue, verified using ex-vivo experiments. This preliminary study maybe further extended to establish the verified proposed concept with different complicated body parts modelled using the software and in-vivo experiments as required to obtain the desired induced field.