Development of High <inline-formula> <tex-math notation="LaTeX">$dB/dt$ </tex-math> </inline-formula> Pulsed Magnetic Field Generator Based on Printed Circuit Board Archimedes Spiral Coil for Biomedical Applications

Abstract

To carry out cell experiments for the pulsed magnetic field treatment of tumor cells, a high $dB/dt$ pulsed magnetic field generator based on a printed circuit board (PCB) Archimedes spiral coil and a self-breakdown air switch is developed. The magnetic field and the induced electric field around the Archimedes spiral coil are calculated. Using COMSOL Multiphysics software, the magnetic field distribution characteristics of the coil are optimally designed. Then, the performance of the generator is measured. Ultimately, the PCB Archimedean spiral coil has seven turns, and it has a diameter of 21 mm. The coil can produce the following pulse magnetic field parameters in a cell culture liquid: an amplitude of 0.92 T, a rise time of 78 ns, a pulsewidth of 1.8 $\mu \text{s}$ , a rate of magnetic field change that reaches $1.1\times 10^{7}$ T/s, a maximum-induced electric field of 55.9 kV/m, a degree of electric field uniformity of 84%, and a maximum-induced current density of $1.7 \times 10^{4}$ A/ $\text{m}^{2}$ . The coil can be used to deliver pulsed magnetic field and induced electric field to biological objects.