The Film Bulk Acoustic Pressure Sensor With Temperature Compensation And Design Of Acquisition System

At present,as the emergence of big data and artificial intelligence,data has played a great role of being as the cornerstone of its development.While the sensor is the main way for people's data acquisition.However,traditional sensors are increasingly unable to meet the public living and production needs due to its a series of deficiencies covering detection precision,range of application and dimension.Based on this,people are eager to find a brand-new type of sensor to satisfy the people's growing needs.With the progress and development of science and technology,products based on film bulk acoustic resonator(FBAR)sensors are gradually entering the consumer market.The FBAR pressure sensor not only has a wide range of applications,also holds a great practical application value.The paper,through the research on the latest research achievement of FBAR pressure sensor,deeply understood the deficiencies of the relevant technologies currently used in the field of temperature compensation.On this basis,the dual-mode characteristics of FBAR resonator with air resonant cavity were mainly studied.In addition,the pressure sensor equipped with temperature compensation or temperature-pressure dual sensor was realized by making full use of its dual-mode characteristics.Finally,a multichannel frequency acquisition system on the basis of thin-film volume acoustic sensor was designed.The main research work and contribution were as follows:(1)The paper,taking the dual-mode characteristics of FBAR as the starting point,placed a film bulk acoustic resonator with the air resonant cavity structure in a sealed container,of which the pressure was controlled by a pneumatic pump.Pneumatic pump controlled sealed container under the range of 17kpa-101.3kpa and 101.3kpa-400kpa,within these two pressure ranges,piezoelectric film bore different types of pressure,that is,compression stress and tensile stress.Both two stresses read to different effects on material properties,which in turn generated different temperature coefficients.The study found that,regarding these two pressure regions,the pressure response and temperature response both held highly linear features.Therefore,a FBAR pressure sensor with temperature compensation or a sensor equipped with dual temperature and pressure measurements was able to be designed.(2)The paper,based on MBVD equivalent model of FBAR,designed Pierce oscillator circuit,amplification circuit and frequency dividing circuit.On the basis of a series of characteristics of FPGA including high speed,high precision and high response,multichannel frequency acquisition system was designed by means of equal precision measurement method,and the collected data were transmitted to STM32 for calculation and displayed further.The system provided a new solution for the study of array sensors and the industrialization of FBAR sensors.The study provides a new scheme for current temperature compensation of FBAR pressure sensor,in the meantime,the emergence of multichannel frequency signal acquisition system also means a step forward for the productization of FBAR sensors,which has certain value and significance for the development of new FBA sensors.