Research Of The Design And Application Technology Of FBAR Based Micro-Mass Sensor

Wireless Sensor Network (WSN) is one of the cutting-edge research fields currentlyin the world, which is a multi-interdisciplinary field and of high knowledge density. It hasattracted much consideration. All the nodes in the sensor network should be of low volume,low power consumption, high sensitivity and high robustness. All these merits can beachieved with FBAR. But unlike other long-existing applications, researches on FBARbased mass sensor start relatively late. So it has large application potential and value.This paper has manufactured Bragg-reflector structured FBARs which havesatisfactory impedance characteristics using laboratory methods. In accordance with thedistinguishing features of the FBAR and current experiment conditions, an SOLTmicrowave test apparatus has been designed for the FBAR to measure the characteristicswithout the probe station. It has nice accuracy and can provide extra beneficial conditions.With the acquired data the parameters in MBVD of the FBAR have been extractedsuccessfully, which leads to the corresponding ADS component library. The model enablesthe FBAR to be directly connected to the circuit in EDA tools for simulation, increasingthe efficiency and dumbing down the design.Also a micro-mass sensing system has been worked out using the FBAR presented inthis thesis. This system uses differential frequency derived from counters to detect thefrequency variation. There are two oscillators, whose outputs are processed by a followingmixer to realize the frequency minus operation, reducing the working frequencydramatically. Then the signal flows through assorted modules like low pass filter, amplifier,wave convertor, digital divider and at length into MCU which displays and stores themeasured results. The whole system has been tuned well and has some basic functionsalready. With this sensing system, the real mass can be determined in terms of thedifferential frequency.