Fabrication and evaluation of a drag-force type dual flow sensor with an embedded temperature sensor

We designed and fabricated a drag-force type dual flow sensor with an embedded temperature sensor. For the wide range detection, two devices in varying length (300 and 700 μm) were used. The corrugated structure was applied for high sensitivity, and the paddle structure was also adopted to enhance the air drag force. The sensor measured the wide range air flow rate from 0.5 up to 8 m/s with a step width at 0.5 m/s. The 700 μm-long sensor showed about 1.5 times larger sensitivity than the 300 μm-long sensor in the low air flow. The results showed that the 700 μm-long device is suitable for low velocity measurements. However, the 300 μm-long sensor showed better sensitivity in the higher air flow; thus, the 300 μm-long sensor is suitable for high velocity measurements. In addition, the embedded temperature sensor measured the basic temperature, and the measured sensitivity was compensated by temperature which could affect the flow sensor. It also showed a linear shape in resistance change related with temperature.