openEMS - a free and open source equivalent-circuit (EC) FDTD simulation platform supporting cylindrical coordinates suitable for the analysis of traveling wave MRI applications

摘要

In this paper, we present a free and open source platform by using the equivalent-circuit finite-difference time-domain (FDTD) method adapted to cylindrical coordinates to efficiently model cylindrically shaped objects. We will address the special characteristics of a cylindrical FDTD mesh such as the mesh singularity at r = 0 and discuss how cylindrical subgrids for small radii can reduce the simulation time considerably. Furthermore, we will demonstrate the applicability and advantages of this cylindrical equivalent-circuit FDTD method to evaluate new types of conformal ring antennas used in the context of high-field (7T) traveling wave magnetic resonance imaging (MRI).