A Multifunctional Surface Acoustic Wave Sensing Module with the Wireless Transmission Function

• Main Author: 蔡明翰
• Other Authors: 張興政
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/81773987776398582234

碩士 === 逢甲大學 === 自動控制工程學系 === 102 === In this study, based on micro-electromechanical systems (Microelectromechanical system, MEMS) technology, design produced can be applied on the tire pressure and temperature measurements wireless tire pressure micro-sensing element. Proposed growth refers to the piezoelectric material is lithium niobate (Lithium niobate, LiNbO3) substrate interdigitated transducer( IDT) electrode, using the piezoelectric effect to generate surface acoustic wave, the form of a surface acoustic wave device using resonance type, the measured frequency drift mainly structure designed upper and lower two-layer structure, can be at the same time the pressure and temperature of the measurement, the upper structure of the pressure sensing portion to back etching reduce the thickness of the substrate to increase its sensitivity, the temperature sensing part using the material characteristics of the lithium niobate to temperature changes linearly, with a radio circuit measurement modules, to complete the multi-function wireless transmission module for surface acoustic wave. Element manufacturing are based on the optical lithography technology, lithium niobate wafer as a substrate, and then use the the deposition machine plated aluminum metal as a sensing electrode, and using the lift-off interdigitated transducer( IDT) in backward etched portion using hydrofluoric acid, acid and alkali resistant due to the lithium niobate itself, only as etching solution, due to the etching time up to 16 hours, so choose gold as a protective layer etching protective layer to complete device fabrication, you can take advantage of the measurement circuit measuring changes in its frequency, thus know the pressure and temperature changes.