Surface acoustic wave resonator device
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsShigefumi Morishita, Yasuo Ebata
Life of this patent
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Abstract
A surface acoustic wave resonator device including a transducer and grating reflectors having an aperture length, wherein the transducer, which is disposed on a piezoelectric substrate, includes a plurality of interdigital transducers connected to each other in series and aligned to form surface acoustic wave propagation paths parallel to each other, the grating reflectors are disposed on opposite sides of the transducer on the piezoelectric substrate, the aperture length of the grating reflectors extending at least the width of said surface acoustic wave propagation paths and preferably being substantially the same effective length as that of the transducer.
Claims20
A surface acoustic wave resonator device comprising:
- a substrate having at least a layer of piezoelectric material;
- at least one transducer means disposed on the surface of said piezoelectric layer for converting an input electrical signal to surface acoustic waves propagating on said piezoelectric surface of the substrate, said transducer comprising a plurality of interdigital transducers electrically connected to each other in series between terminals to which the input electrical signal is applied and aligned to form surface acoustic wave propagation paths parallel to each other, and said interdigital transducers each having first and second electrodes with finger electrodes arranged in an interdigitated relationship;
- and
- grating reflector means having an aperture length and disposed on said piezoelectric surface for reflecting the surface acoustic waves, said reflector means including a plurality of parallel spaced reflecting elements arranged in parallel to said finger electrodes of said interdigital transducers and a spacing between adjacent reflecting elements is equal to a spacing between adjacent finger electrodes of said interdigital transducers, and said aperture length of said grating reflector means extending at least the width of said surface acoustic wave propagation paths.
A surface acoustic wave resonator device comprising:
- a piezoelectric substrate;
- an input transducer disposed on said piezoelectric substrate for converting an input electrical signal to surface acoustic waves propagating on said piezoelectric substrate;
- an output transducer disposed on said piezoelectric substrate in a face to face relationship with said input transducer for converting the surface acoustic waves to an electric signal, at least one of said transducers comprising a plurality of interdigital transducers which are connected to each other in series between a pair of signal terminals and aligned in a direction perpendicular to the surface acoustic wave propagation path;
- and
- first and second grating reflectors, disposed on said piezoelectric substrate with said input and output transducers therebetween, for reflecting the surface acoustic waves, the aperture length of said first and second grating reflectors extending at least the width of said surface acoustic wave propagation paths.
A surface acoustic wave resonator device comprising:
- a piezoelectric substrate capable of supporting propagating surface acoustic wave energy;
- a plurality of interdigital transducers coupled to a surface of said substrate and connected to each other in series and aligned to form surface acoustic wave propagation paths parallel to each other, and said interdigital transducer each comprising a plurality of substantially parallel spaced-apart conductive electrodes arranged in an interdigitated relationship, the traverse overlap between adjacent electrodes varying along the surface acoustic wave propagation direction;
- and
- grating reflector means having an aperture length and disposed on said piezoelectric substrate for reflecting the surface acoustic waves, said aperture length of said grating reflector means having substantially the same effective length as total aperture length of said interdigital transducer.
Dependencies are inferred from the claim text.