Surface Wave Resonator Having Reduced Parasitic Resonance
First Claim
1. A surface acoustic wave resonator produced on a cut substrate with propagation axes for which a nonzero directivity exists and comprising at least one central transducer (Tc) exhibiting a central axis, a first array of reflectors (R1) and a second array of reflectors (R2), said arrays being situated on either side of said transducer, wherein the two arrays of reflectors exhibit nonsymmetric configurations with respect to the central axis of said central transducer, the first and/or the second arrays of reflectors exhibiting over a portion of reflector units, a variation in periods of said reflectors.
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Abstract
The invention relates to a surface acoustic wave resonator produced on a cut substrate with propagation axes for which a nonzero directivity exists and comprising at least one central transducer (Tc) exhibiting a central axis, a first array of reflectors (R1) and a second array of reflectors (R2), said arrays being situated on either side of said transducer, characterized in that the two arrays of reflectors exhibit nonsymmetric configurations with respect to the central axis of said central transducer.
The introduction of an asymmetry makes it possible to strongly attenuate the parasitic resonances which may appear when the resonators are produced notably on piezoelectric substrates of quartz type or any other material and cut with propagation axes for which there exists a natural directivity (LiTaO3, LiNbO3, langasite, GaPO4, LiB407, KNbO3, etc.)
12 Citations
7 Claims
- 1. A surface acoustic wave resonator produced on a cut substrate with propagation axes for which a nonzero directivity exists and comprising at least one central transducer (Tc) exhibiting a central axis, a first array of reflectors (R1) and a second array of reflectors (R2), said arrays being situated on either side of said transducer, wherein the two arrays of reflectors exhibit nonsymmetric configurations with respect to the central axis of said central transducer, the first and/or the second arrays of reflectors exhibiting over a portion of reflector units, a variation in periods of said reflectors.
Specification