Browsing by Author "Ma, Shenhui"

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A CMOS-MEMS Thermoresistive Micro Calorimetric Flow Sensor With Temperature Compensation
(2019-10-01)
Xu, Wei
;
Ma, Shenhui
;
Wang, Xiaoyi
;
Chiu, Yi
;
Lee, Yi-Kuen
In this paper, we propose a new 1D thermoresistive micro calorimetric flow (TMCF) sensor model for moist airflow with the temperature-dependent thermophysical properties. The 1D model and the corresponding proposed equivalent circuit model enable rapid design optimization of an ambient temperature-compensated TMCF ((TMCF)-M-2) sensor integrated with the interface circuit by using a commercial 0.35-mu m 2P4M CMOS MEMS technology. The fabricated sensor shows a prominent sensitivity of 0.543 V/(m/s) and a low power consumption of less than 2.8 mW. Moreover, in comparison with the large drifting of 49% for the uncompensated TMCF sensor, the (TMCF)-M-2 sensor's output has an ultralow drifting of 0.5% with the ambient temperature variation of 22 degrees C similar to 48 degrees C. Therefore, this robust (TMCF)-M-2 sensor can be a promising Internet of Things (IoT) for smart energy-efficient buildings.
LOW-COST TEMPERATURE-COMPENSATED THERMORESISTIVE MICRO CALORIMETRIC FLOW SENSOR BY USING 0.35 mu m CMOS MEMS TECHNOLOGY
(2016)
Xu, Wei
;
Gao, Bo
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Ma, Shenhui
;
Zhang, Anping
;
Chiu, Yi
In this paper, a low-cost Temperature-compensated Thermoresistive Micro Calorimetric Flow ((TMCF)-M-2) sensor by using a commercial 0.35 mu m 2P4M CMOS MEMS technology is reported. For nitrogen flow, the fabricated (TMCF)-M-2 sensor achieves a normalized sensitivity of 230 mV/(m/s)/mW with respect to the input heating power, which is two orders of magnitude better than the reported micro calorimetric flow sensors. The experimental results of (TMCF)-M-2 sensor under different ambient temperatures T-a of 22 degrees C similar to 48 degrees C showed the excellent temperature insensitive output with the maximum normalized variation of 0.5%. Compared to the uncompensated counterpart (49%), it demonstrates our robust (TMCF)-M-2 sensor design is applicable for the integration of on-chip CMOS electronics for the Internet of Things.
Theoretical and Experimental Investigations of Thermoresistive Micro Calorimetric Flow Sensors Fabricated by CMOS MEMS Technology
(2016-10)
Xu, Wei
;
Song, Kui
;
Ma, Shenhui
;
Gao, Bo
;
Chiu, Yi
A general 1-D model was presented to predict the characteristics of CMOS thermoresistive micro calorimetric flow (TMCF) sensor with two types of packaging, i.e., open-space type and channel type, for both gases and liquids. The 1-D model was first validated by a numerical computational fluid dynamics (CFD) model and was subsequently normalized for different fluids flow. Notably, the model proposed by Nguyen and Dotzel is a special case of our 1-D model. The normalized output of TMCF sensor is a function of normalized input parameters of Reynolds number Re and Prandtl number Pr. The scaling analysis of the sensor output, sensitivity, and power consumption was performed to optimize the design of TMCF sensors in terms of key design parameters, including the thin film thickness, the height of bottom cavity, and so on. Accordingly, three pairs of TMCF sensors were designed and fabricated by using a 0.35 mu m 2P4M CMOS microelectromechanical systems technology. The fabricated sensors showed a normalized sensitivity of 230 mV/(m/s)/mW for nitrogen gas flow, which was two orders of magnitude higher than the previous CMOS flow sensors. Therefore, the proposed 1-D model is a promising tool for the sensor\'s system-level design with the on-chip microelectronics for the Internet of Things. [2016-0098]