Single-ended pair SAW resonator with high quality factors

Abstract

The invention relates to a single-ended pair SAW resonator with high quality factors. The single-ended pair SAW resonator comprises a piezoelectric substrate (22), an interdigital transducer (24), a first reflector (23) and a second reflector (25), wherein the interdigital transducer (24) is placed on the surface of the piezoelectric substrate (22), and the first reflector (23) and the second reflector (25) are distributed on the two sides of the interdigital transducer (24). The edge space between the first reflector (23) and the interdigital transducer (24) and the edge space between the second reflector (25) and the interdigital transducer (24) are both 0.625 lambada, and the lambada is the wave length of sound waves. The interdigital transducer (24) is of a Blackman window function trimmed mean weight structure. Aluminum material electrodes are all used in the interdigital transducer (24), the first reflector (23) and the second reflector (25), and the duty ratio of the electrodes is 1.3-1.5. The film thickness of the aluminum electrode of the interdigital transducer (24), the film thickness of the aluminum electrode of the first reflector (23) and the film thickness of the aluminum electrode of the second reflector (25) are 1.1-1.5% lambada. The single-ended pair SAW resonator has the advantages of being small in size, high in Q value, small in OOB fluctuation and the like.

Description

technical field [0001] The present invention relates to a surface acoustic wave resonator (hereinafter referred to as a SAW resonator) in acoustic technology, in particular to an asynchronous monolithic resonator with high quality factor, small volume and small in-band fluctuation for temperature and pressure sensors. End-to-surface acoustic wave resonators. Background technique [0002] Single-ended pair SAW resonators with high quality factors are widely used in high frequency stability acoustic wave oscillators. In recent years, single-ended pair SAW resonators have been widely used in various surface acoustic wave sensors due to their simple structure, high quality factor (Q value) and low loss. Especially in some surface acoustic wave temperature sensors (such as the power equipment temperature sensing system launched by Sengenuity Company in the United States), pressure sensor systems for automobile tire pressure monitoring (such as the three resonator system launched...

AI Technical Summary

Problems solved by technology

The problem with this synchronous structure is that its in-band fluctuation is relatively large, which may lead to one or more false resonance points, and the Q value is also low, which directly affects the performance of the above wireless sensor

In order to improve its quality factor, relatively long reflectors are generally used (Waldemar S, "Scattering matrix approach to one-port SAW resonator", IEEE UFFC, Vol.47, No.6, 2000, pp:1615-1618), although A higher Q value is obtained, but the out-of-band fluctuation is also increased, and the area of ​​the device is greatly increased, thereby increasing the volume of the sensor, which is not conducive to the practical application of the sensor

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