Simulation on the eddy current sensor based on micro electroforming coil

In order to analysis the property of the eddy current sensor based on the micro planar coil, the magnetic model was built and deduce the expression of output signal. The relation between the measure result and the input signal, gap distance, measure target was simulated with the FEM software. The test result indicate that the amplitude of the output signal increased with the increasing of the amplitude and frequency of the input signal, decreased with the increasing of the gap distance; Under the same condition, the output signal was high when the permeability of the measure target was high. The optimal sensitivity was 0.55 mv/μm and the optimal measure range was 500μm, when the material of measure target was nickle and the signal (50 kHz, 140mv) was adopted. The study was a high efficiency and simple method without complex calculation, was benefit to the practice of magnetic sensor based on the micro planar coil.