A pressure sensor made of two piezoresistive bridges

A double piezoresistive bridge, which can improve sensor sensitivity, cancell zero pressure offset and decrease thermal sensitivity drift, is presented. The most distinguishing feature of this sensor is that the output polarity of two bridges is opposite as applying pressure to the bridges, and there is the same output polarity without the pressure on the bridges. After subtracting one from another, the pressure sensitive output is twice as large as that of a single-bridge, and the zero pressure output to depend on temperature is cancelled. When the sensor is made of diffused resistors with high level, it will have lower thermal sensitivity drift. The expectative results have been obtained in the modelling experiments.