Heterogeneous Integrated Wireless Displacement Sensor

Abstract

© 1965-2012 IEEE. In this paper, a new design of a heterogeneous integrated wireless sensor for displacement measurement is presented. The designed sensor consists of an inductor fabricated in printed circuit board technology, as an essential part, a spacer, and an electrode on a flexible polyimide foil as membrane. The proposed design of a sensor enables wireless displacement measurements using an external inductor as an antenna. Deflecting the polyimide membrane draws the electrode close to the coil of inductor (as bottom electrode) and causes an increase in the capacitance between them which changes the resonant frequency of the sensor. Displacement is wirelessly measured by phase-dip method determining the change of the resonant frequency of the antenna sensor system. The measurement of the sensor is performed and the characteristic of the sensor is obtained. Displacement is measured up to 500 μm in the steps of 50 μm, and the resulting sensitivity of designed sensor is 16.2 kHz/μm.