A new approach to the solution of Maxwell's equations for low frequency and high-resolution biomedical problems

Abstract

High spatial resolution studies of the interaction of the human body with electromagnetic waves of low frequency presents a difficult computational problem. As these studies typically require at least $10^4$ points per wavelength, a huge number of time steps would be needed to be able to use the finite difference time domain method (FDTD). In this paper, a new technique is described, which allows the FDTD method to be efficiently applied over a very large frequency range, including low frequencies. In the method, no alterations to the properties of either the source or the transmission media are required. The method is essentially frequency independent and has been verified against analytical solutions within the frequency range 50 Hertz to 1 Gigahertz. As an example of the lower frequency range, the method has been applied to the simulation of electromagnetic field behavior in the human body exposed to the pulsed magnetic field gradients of a magnetic resonance image (MRI) system.