Development of an hybrid 3D FEM for the modeling of micro-coil sensors and actuators

In this study a method for the modeling of micro-coil sensors and actuators at high frequency is presented. The goal of the modeling is to determine the elements of an electric equivalent circuit. A magneto-dynamic 3D finite element formulation is used to calculate the resistance and the inductance of the micro-coil at high frequency. Using the previous finite element results, an electrostatic 3D finite element analysis is then used to determine the capacitance. Two different structures of planar micro-coils are characterized: a spiral micro-coil fabricated on a glass substrate and a square micro-coil fabricated on a gallium arsenide substrate. The numerical results obtained with the proposed method are then compared with measurements and analytical results.