P-matrix model and experimental analysis of surface acoustic wave mass sensor

The frequency domain properties of Y type dual path surface acoustic wave(SAW) mass sensors with new structures were investigated experimentally and theoretically using P-matrix calculation model.The performance of three devices with different structures was compared.By using apodized interdigital transducer(IDT) compared with uniformed IDT,the triple transverse interference(TTI) and multiple reflections were decreased,the side lobe rejection was increased by 15 dB,the equivalent Q value was improved from 4 800 to 8 689 in oscillation mode,and the short term frequency stability was increased by-1.81 dBc/Hz.By using slanting reflector,the bandpass ripple due to edge reflection was reduced by 2 dB,the equivalent Q value was improved from 8 689 to 12 477 in oscillation mode,and the short term frequency stability was increased by-1.20 dBc/Hz.Therefore,higher equivalent Q value and better short term frequency stability are readily achievable using slanting reflector and apodized IDT in oscillation mode.