Optimization of the Coil to Focalize the Electrical Field Induced by Magnetic Stimulation in the Human Brain

The design of the magnetic stimulating coil is one of the key technique in the magnetic stimulating system, it is the hotspot in the research of magnetic stimulation. A coefficient to evaluate the focus of the electrical field intensity induced by magnetic stimulation is firstly presented in this study, which was used as an index of focus, Matlab was used as the tool to simulate the distribution of induced electrical field, result is obtained that the four-leaf rose shape coil is the best compared with other five different shapes of coil. As a result of optimizing other parameters of the coil, the smaller radius of the coil is the better choice and the angle between four-leaf rose coil of 102 degree is better than other value. Furthermore, when the four-leaf coil with angle of 112 degree assembled with a coil of 89, the more focused electrical field is obtained. The coefficient proposed in this study may be a guideline to the optimization of the coil's parameters.