Aiming at requirement of integration study of radio frequency identification（ RFID） and wireless sensor networks（ WSNs） technology

an integrated acceleration sensor is designed based on 0. 35 μm CMOS process.Sensor unit utilizes deep reactive ion etching procedure on the backside of the monocrystalline silicon substrate

and then employs anisotropic etching on the front side of the metal and dielectric composite layer. The sensor interface circuit is based on phase-locked loop theory

converts sensor signal to frequency domain avoid usage of ADC which has very high power consumption and achieves capacitance to digital conversion directly. The measurement results prove that the proposed acceleration sensor achieves high performance on linearity

stability and power consumption

which is especially suitable for application on passive RFID and other ultra-low power consumption field.