Super Convenient And High Sensitivity Gas And Humidity Sensors

The rapid development of industrial and agricultural production is often accompanied by environmental pollution.So the focus of this paper is how to detect various gases quickly and accurately on the premise of ensuring production efficiency.Previous research results of sensors are mostly active sensors.Although these sensors have the advantages of short response recovery time and sensitivity,there are some shortcomings,such as power supply,high working temperature,short service life,and so on.Therefore,their application fields are limited.In view of the limitations about the above active sensors,this paper reports a passive sensor design with improved sensitivity.The sensor can be tested at room temperature by a reasonable method.The main contents of this paper are as follows:In this paper,the design of a gas and humidity sensor for improving sensitivity is introduced.The two improved models are simulated by HFSS software of Ansys Company.The structure parameters in a reasonable range are obtained,and the better improved structure is selected.The sensor integrates Carbon nanotubes(CNT)and microstrip antenna on the same plane.When exposed to different gas or humidity environments,the conductivity of the sensor is changed by physical adsorption of gas and water molecules through CNT film,thus changing the operating frequency of the antenna to realize the function of the sensor.Sensor sensitivity is improved by using the idea of replacing part of patch conductor with CNT film band.The replaced patch plays a dominant role in antenna radiation,which can better affect the frequency change,and can make CNT film have the greatest impact on antenna radiation.Subsequent experiments built a test platform.In the sealed environment with constant temperature and humidity,the sensor prototype was filled with several different gases,and then the humidity of the sensor was tested by water vapor.Through the performance test of the sensor,it is concluded that in the carbon dioxide environment,the maximum frequency shift of the gas sensor is 13 MHz;the frequency shift of the gas sensor is about 9 MHz in the oxygen and ammonia environment;in the humidity environment,the frequency shift is about 35 MHz.The experimental results show that the gas sensitivity of the improved CNT antenna sensor is better than that of the CNT gas sensor integrated on the top of the patch resonator reported so far.The working frequency of the sensor is 2.4 GHz.It has a wide range of applications.It is compatible with Wi-Fi,Bluetooth and other devices and is easy to integrate into the sensor network.The geometric structure of the sensor can also be easily extended to other frequencies,conforming to the application equipment.The passive gas sensor proposed in this paper has great prospects in the fields of environmental monitoring,weather forecasting and the application of special industrial production.