2-D Axisymmetric Modeling of Circular PCB Coils and Solenoids in COMSOL Multiphysics

In this paper, a 2-dimentional (2-D) axisymmetric modeling is presented for biomedical circular printed circuit board (PCB) coils and solenoids in COMSOL Multiphysics. With this model, the number of required meshes in finite element method (FEM) based simulations is reduced, which speeds up the iterative design procedure of inductive links in biomedical implants. While having a good accuracy, the presented 2-D axisymmetric modeling reduces the extraction time of electromagnetic parameters of PCB coils and solenoids by about 90%, compared to 3-D modeling. In order to investigate the accuracy of presented 2-D modeling, we have fabricated a PCB coil and a solenoid with suitable geometries for implantation in body. The measurement results of electromagnetic parameters have a good agreement with the 2-D modeling based simulation results, and they verify each other. Finally, using the presented 2-D modeling, a comprehensive parametric simulation has been performed to study the behavior of coupling coefficient (k) and the maximum achievable k of PCB coils as a function of geometric parameters.