Linearity and Sensitivity Analysis of MEMS Thermal Wind Sensor via Analytical Model

Abstract

In this article, an analytical model focusing on the linearity and sensitivity of micro-electromechanical systems (MEMS) thermal wind sensors with low thermal conductivity substrate (LTCS) and packaging is proposed. The influence of substrate material, substrate thickness, heater size, measurement distance, packaging material, and packaging size on the sensor performances are investigated to serve as design guidelines for future thermal wind sensors. For the first time, model results reveal that all the factors listed above have opposite effects on the sensitivity and linearity of the wind sensors. Furthermore, sensitivity and linearity are related to power consumption and measurement range respectively. Therefore, a compromise between sensitivity and linearity is required for high wind speed measurement applications. The real wind sensor fabricated with ceramic substrate and encapsulated by a plastic carrier was tested in a wind tunnel. The experimental results illustrated that the sensitivity of the sensor at 3.3 m/s is 157 mV/( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{W}\cdot \text{m}\cdot \text{s}^{-1}$ </tex-math></inline-formula> ). In addition, the fitting linearity parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$B_{m}$ </tex-math></inline-formula> is 0.424 in the range from 0 to 33 m/s.