High Sensitivity Pressure Sensor Using Tandem Wheatstone Bridge for Low Pressures
Yuanying Zhang, Wei Cui, Jinjun Deng, Xiubing Liang, Xiaoliang Luo, Xiaojing Wang, Binghe Ma, Jian Luo
Abstract
A Tandem Wheatstone Bridge Low-Pressure (TWBLP) sensor with high sensitivity which can be widely used in medical and industrial fields has been designed and fabrication. Compared with the Conventional Low-Pressure (CLP) sensor, the TWBLP sensor membrane is arranged with eight piezoresistors, which are formed into two Wheatstone Bridges. They achieved the detection of membrane stress with different positions and different directions. The output ports of the two Wheatstone Bridges are connected in tandem to realize the on-interference superposition of the output electric potential, thus improving the sensitivity of the sensor. The structure of the sensor membrane and the position of the piezoresistors are calculated by the Finite Element Analysis (FEA). The TWBL sensor is simple in structure and easy to produce in large quantities, with the advantage of high sensitivity, it can provide tiny pressure measurement results for pressure measurement in related fields. In the laboratory environment, the local atmospheric pressure is used as the reference zero point to calibrate the sensor. The test results show that the sensitivity of the TWBLP sensor is 28.2% higher than that of the CLP sensor. When the sensitivity is in the range from -10kPa to 10kPa, the sensitivity reaches 23.07mV /kPa, and the measurement accuracy is 0.19%F.S.