High-sensitivity two-port resonant surface acoustic wave detector

Abstract

The invention relates to a two-port resonant surface acoustic wave detector, comprising a two-port resonator produced on a substrate (1), wherein a second interdigital transducer (3) is arranged on the substrate (1); a first interdigital transducer (2) and a third interdigital transducer (4) are arranged at two sides of the second interdigital transducer (3); an interval (7) is formed between the second interdigital transducer (3) and the first interdigital transducer (2); the interval (8) is formed between the second interdigital transducer (3) and the third interdigital transducer (4); a first metal reflecting grating array (5) is arranged at the other side of the first interdigital transducer (2); a second metal reflecting grating array (6) is arranged at the other side of the third interdigital transducer (3); the interval (7) is equal to the interval (8) and is 0-3.5 times of the wavelength of the interdigital transducers.

Description

technical field [0001] The invention relates to a surface acoustic wave detector, in particular to a high-sensitivity double-terminal pair resonant surface acoustic wave detector for sensors. Background technique [0002] The surface acoustic wave (SAW) detector is used as the frequency control element of the surface acoustic wave oscillator, and its performance directly affects the frequency stability of the oscillator. According to the frequency stability principle of the surface acoustic wave oscillator, the quality factor (Q value) and the insertion loss of the surface acoustic wave detector directly affect the short-term frequency stability of the oscillator. The higher the Q value, the lower the insertion loss, the The higher the short-term frequency stability of the oscillator, the frequency stability of the surface acoustic wave oscillator directly affects the lower detection limit and sensitivity of the SAW gas sensor. Generally, there are roughly two device struct...

AI Technical Summary

Problems solved by technology

However, in the prior art, in order to increase the sensitive area of ​​the resonator, the spacing between the interdigital transducers of the resonator is set wider (greater than ten wavelengths), thus resulting in a longer resonant cavity, such that the energy distribution area in the resonant cavity big, not concentrated enough

When detecting a small amount of analytes, the analytes are mainly distributed in the center of the sensitive area of ​​the resonator, and the energy distribution characteristics of the existing long resonant cavity prevent the energy from being concentrated in the center of the resonator, resulting in the sensitivity of the central area Not high enough to accurately detect trace analytes

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