Novel structure SAW mass sensor

Y-type structure of dual delay line mass sensor with slanting metal array reflectors was developed based on multi-strip coupler. The novel structure can not only avoid the bulk wave efficiently, but also reduce the triple-transit-interference (TTI) and multiple reflections. P-matrix was used to analyze the sensor properties. Sensitivity of the sensors has been tested by means of the delay line active oscillation circuit and network analyzer. Both theoretical and experimental results show the slanting metal array reflector designed between output inter-digital transducer (IDT) and chip edge can suppress the spurious signal reflected from the chip edge and improve the sensitivity of the sensor. A very low relative temperature coefficient of the sensors is obtained(only about 6.2Hz/°C). The Q value of the sensors is 1.1×10⁴. Mass loading effect sensitivity is as high as 23.29ng/ppm·cm² with a good linearity.