Surface acoustic wave resonator and surface acoustic wave filter

By using a reflector grating structure combining interdigital reflector gratings, short-circuit reflector gratings, and open-circuit reflector gratings in the surface acoustic wave filter, effective suppression of longitudinal wave modes and frequency shift are achieved, solving the insertion loss problem caused by longitudinal wave modes and improving filter performance.

CN122268314APending Publication Date: 2026-06-23MAXSCEND MICROELECTRONICS CO LTD
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Patent Information

Application Number
CN202610621950.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-05-07
Publication Date
2026-06-23

AI Technical Summary

Technical Problem

Existing surface acoustic wave (SAW) filters suffer from parasitic ripples excited by longitudinal wave modes, which degrades the filter's passband insertion loss, increases insertion loss, and affects the performance of communication equipment.

Method used

A reflector grating structure combining interdigital reflector gratings, short-circuit reflector gratings, and open-circuit reflector gratings is adopted. Through multi-level destructive interference and gradient acoustic boundary design, the frequency spacing between the longitudinal wave and the resonant point is adjusted, the longitudinal wave resonance peak is suppressed, and it is moved to a frequency band far away from the stopband.

Benefits of technology

It effectively reduces insertion loss, improves the passband flatness of the filter, and enhances the stability and reliability of surface acoustic wave devices.

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Abstract

The invention relates to the technical field of resonators, and discloses a surface acoustic wave resonator and a surface acoustic wave filter, the surface acoustic wave resonator comprises a piezoelectric layer, an interdigital transducer and a reflecting grating structure, the interdigital transducer and the reflecting grating structure are arranged on the piezoelectric layer along a first direction, and the reflecting grating structure is located at the side part of the interdigital transducer; the reflecting grating structure comprises a plurality of unit reflecting gratings which are arranged along a first direction, and finger strips of each unit reflecting grating extend along a second direction; the structure of each unit reflecting grating is an interdigital reflecting grating, a short-circuit reflecting grating or an open-circuit reflecting grating; in the reflecting grating structure, at least one unit reflecting grating is an interdigital reflecting grating, and the unit reflecting gratings except the interdigital reflecting grating are one or two of short-circuit reflecting gratings or open-circuit reflecting gratings. According to the invention, the influence of the longitudinal wave of the surface acoustic wave resonator on the filter passband can be weakened, the insertion loss is reduced, the flatness of the filter passband is improved, and a high-stability and low-loss surface acoustic wave device is realized.
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