Wireless Passive Humidity Sensor Based On SAWR

Now,in order to accurately obtain information from the outside world,sensors are needed.As one of the core technologies of the Internet of Things,sensors are a key factor in improving the quality of life and social development.Among them,humidity sensors play a major role in life,industry,biology,chemical industry,food and health,hospitals and other fields,while traditional humidity sensors mostly adopt active wired methods.On the one hand,such sensors It will bring environmental pollution.On the one hand,it is impossible to measure the humidity in a closed and dangerous area,which limits its own development.This paper designs a wireless passive humidity sensor,which mainly combines a Surface Acoustic Wave Resonator(SAWR)with an impedance type humidity sensor.The sensor first responds to changes in humidity as changes in impedance,and changes in impedance The frequency change of the SAWR is pulled,and the frequency change can be wirelessly measured by the reader to reflect the humidity change.The results show that the sensor shows a linear frequency response to humidity in the range of 10% RH-40% RH,a sensitivity of about 0.5KHz /% RH,and a 1KHz /% RH in the range of 40% RH-50% RH.Sensitivity.Sensitivity is increased to 1.5k Hz /% RH in the range of 50% RH-70% RH,and 3KHz /% RH is displayed in the range of 70% RH-80% RH.The greater the humidity,the higher the sensitivity.This kind of sensor has solved the deficiency of the active humidity sensor,it has very important meaning.The main research contents of the paper are as follows:(1)First,a simulation method of SAWR external impedance sensor is proposed,and the frequency characteristics of SAWR external impedance sensor are simulated using ADS software to guide the sensor design.(2)A graphene oxide and gold interdigital transducer was used to make an impedance humidity sensor,and the characteristic relationship between impedance and humidity parameters was studied.This impedance humidity sensor and SAWR were used to form a wireless passive humidity sensor based on SAWR,Design the matching circuit to connect the antenna,and complete the design of the wireless passive humidity sensor.(3)Using ADS software,network analyzer,and reader to study the relationship between the humidity parameter and the resonance frequency,and analyze the three results to prove that the designed wireless passive humidity sensor based on SAWR has a high measurement Accuracy,can achieve humidity measurement within 50 cm range.