A 4 × 4 array multichannel magnetic stimulation system using submillimeter sized planar square spiral coils: The spatial distribution of electromagnetic field

Article type: Research Article

Authors: Tian, Lei^a | Song, Limei^b | Zheng, Yu^a; | Wang, Jinhai^a

Affiliations: [a] School of Life Science, Tiangong University, Tianjin, China | [b] School of Artificial Intelligence, Tiangong University, Tianjin, China

Correspondence: [*] Corresponding author: Yu Zheng, School of Life Science, Tiangong University, China. Tel.: +86 18222128406; E-mail: zhengyu@tiangong.edu.cn

Abstract: Multi-coil magnetic stimulation has advantages over single-coil magnetic stimulation, such as more accurate targeting and larger stimulation range. In this paper, a 4 × 4 array multichannel magnetic stimulation system based on a submillimeter planar square spiral coil is proposed. The effects of multiple currents with different directions on the electromagnetic field strength and the focusing zone of the array-structured magnetic stimulation system are studied. The spatial distribution characteristics of the electromagnetic field are discussed. In addition, a method is proposed that can predict the spatial distributions of the electric and magnetic fields when currents in different directions are applied to the array-structured magnetic stimulation system. The study results show that in the section of z = 2 μm, the maximum and average magnetic field strengths of the array-structured magnetic stimulation system are 6.39 mT and 2.68 mT, respectively. The maximum and average electric field strengths are 614.7 mV/m and 122.82 mV/m, respectively, where 84.39% of the measured electric field values are greater than 73 mV/m. The average magnetic field strength of the focusing zone, i.e., the zone in between the two coils, is 3.38 mT with a mean square deviation of 0.18. Therefore, the array-structured multi-channel magnetic stimulation system based on a planar square spiral coil can have a small size of 412 μm × 412 μm × 1.7 μm, which helps improving the spatial distribution of electromagnetic field and increase the effectiveness of magnetic stimulation. The main contribution of this paper is a method for designing multichannel micro-magnetic stimulation devices.

Keywords: Multichannel micro-magnetic stimulation, planar square spiral coils, 4 × 4 coil array, spatial distribution of electromagnetic field

DOI: 10.3233/JAE-210139

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 3, pp. 329-346, 2022