An analytical model of an eddy current sensor designed for noncontact distance measurement was presented. The device consists of two planar coil (driver coil and pickup coil) stacked on the magnetic core. The planar coil fabricated by UV-LIGA technology with SU8 photoresist was illustrated, and the permalloy magnetic core electroforming process was presented also. Tested with 10–50KHz sine signal, the output voltage on the sensing coil rearched 30mv with an stainless target placed at a distance of 10μm, and the experimental showed a linear relation between the distance and output voltage within 50μm distance. The whole size of the device was: Φ5mm × 1.5 mm. The results demonstrated that the device could nondestructive evaluate the distance and be easily integrated on chip.

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