Study of Wireless Capacitance – Inductance Coupling Microsensors for Liquid Level Measurement

• Main Authors: Yi-Chen Li, 李宜真
• Other Authors: Hsing-Cheng Chang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/03055723257423897018

碩士 === 逢甲大學 === 產業研發碩士班 === 97 === This paper presents a wireless capacitance-inductance coupling microsensor for liquid-level measurement. The microsensor consists of a parallel-plate capacitor, a planar coil inductor and a polyimide thin film. An inductor-capacitor (LC) resonant circuit is provided for measuring liquid-level by analyzing the shift of resonance frequency. The development of sensors is following the procedures of simulation, design, fabrication, and test. The MEMS (Microelectromechanical System) fabrication technology is used to minimize device dimension and to increase production efficiency. Based on passive wireless transmission and sensing circuit design, the microsensor can be constantly measuring without supplying electrical power source. The wireless signal measurement system includes an arbitrary function generator, a spectrum analyzer, an RF power amplifer and signal processing circuits. The typical sensor dimension is 8mm×8mm×0.77mm that contains a 61-turns nickel-electroplated micro-coil inductor and a capacitor with an area of 5000μm×5000μm.