Surface acoustic wave sensor

The invention relates to a surface acoustic wave sensor. The surface acoustic wave sensor comprises a piezoelectric substrate, double-ended pair interdigital electrodes, two reflecting gratings and aninsulating layer; the two interdigital electrodes are oppositely arranged on the upper surface of the piezoelectric substrate, and a gap is formed between the two interdigital electrodes; the two reflecting gratings are arranged on the two sides of the two interdigital electrodes respectively, and the two interdigital electrodes are located between the two reflecting gratings; the upper surface of the piezoelectric substrate in the area where the two interdigital electrodes are located, the upper surface of the piezoelectric substrate located between the two interdigital electrodes and the upper surfaces of the interdigital electrodes are covered with the insulating layer. According to the surface acoustic wave sensor, the mass load effect sensitive characteristics of an acoustic wave propagation region and an el