A novel method to eliminate the co-channel interference of micro-machined diffused silicon resonant pressure sensor

A novel structure of micro-machined resonant pressure sensor with diffused silicon as the resonant beam is proposed in this paper. To improve the signal to noise ratio (SNR) of the sensor so as to realize the close-looped control of electromagnetic excitation and detection easily, the micro-structure of the sensor was introduced and analyzed firstly. It is found that the co-channel interference resulting from the capacitance from the electrodes and diffused silicon layer of the sensor is the main noise resource. And then the equivalent circuit model for the micro-structure of the sensor is brought up, moreover the methods to reduce the co-channel interference were tried and discussed. Thus a novel measure with nonsymmetrical excitation was proposed. Experiments show that this measure can effectively eliminate the co-channel interference of the sensor and the SNR is improved from 1.53 to 35, which provide the effective ways to close-looped excitation and detection for the sensor.