A Gas Medium Approach To Sensitivity Improvement Of MEMS-Based Thermal Acoustic Particle Velocity Sensors

Micro-fabricated thermal acoustic vector sensor can directly measure the vibration velocity of sound particles. However, due to the limitation of thermal capacity of thermistor and heat transfer rate, the sensitivity of the sensor is very low at high frequencies. This paper presents a method of improving the sensitivity of thermal acoustic sensors for the first time by changing its working medium. Both simulation and experiment have been carried out to verify this method. The simulation results showed that the sensitivity of the sensor in sulfur hexafluoride under a standard atmospheric pressure was 14dB higher than that in air. The experimental results showed good agreement with simulation results. Besides, the noise of APVS was almost at the same level in different gas mediums. Therefore, the signal to noise ratio has been improved.