Resonator structure
AssigneeRF Monolithics, Inc.
InventorPeter V. Wright
Life of this patent
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Abstract
A surface acoustic wave resonator device having a resonant cavity formed on a substrate between a transducer and its related grating that causes a symmetric frequency response with one major resonant frequency response and low spurious frequency responses, with no etched grooves or recessed electrodes, with a minimum electrode geometry of .lambda./4, with single level fabrication and uniform wave velocity throughout the structure and being frequency insensitive to electrode reflections.
Claims13
A resonator structure comprising:
- a. a piezoelectric substrate,
- b. first and second spaced gratings of .lambda./4 electrodes attached to said substrate,
- c. input and output spaced transducer structures having .lambda./4 electrodes and attached to said substrate between said first and second gratings for generating standing waves in said substrate, and
- d. an aperiodic cavity formed on said substrate between only one of said gratings and one of said transducers.
A method of forming a resonator structure comprising the steps of:
- a. attaching first and second spaced gratings of .lambda./4 electrodes to a piezoelectric substrate,
- b. attaching input and output spaced transducer structures having .lambda./4 electrodes to said substrate between said first and second gratings for generating standing waves in said substrate, and
- c. forming an aperiodic cavity on said substrate between only one of said gratings and one of said transducers.
A resonator filter structure comprising:
- a. a piezoelectric substrate,
- b. first and second spaced gratings of .lambda./4 electrodes attached to said substrate,
- c. input and output spaced transducers having .lambda./4 electrodes and attached to said substrate between said first and second gratings for generating standing waves in said substrate,
- d. a coupler grating positioned on said substrate between said input and output transducers,
- e. a first aperiodic cavity formed on said substrate between said input transducer and said first grating, and
- f. a second aperiodic cavity formed on said substrate between said coupler grating and said output transducer.
A method of forming a resonator filter structure comprising:
- a. attaching first and second spaced gratings of .lambda./4 electrodes to a piezoelectric substrate,
- b. attaching input and output spaced transducers having .lambda./4 electrodes to said substrate between said first and second gratings for generating standing waves in said substrate,
- c. positioning a coupler grating on said substrate between said input and output transducers,
- d. forming a first aperiodic cavity on said substrate between said input transducer and said first grating, and
- e. forming a second aperiodic cavity on said substrate between said coupler grating and said output transducer.
Dependencies are inferred from the claim text.