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US 6,271,739 B1Granted
Surface-acoustic-wave device having an improved pass-band characteristic and an improved degree of freedom for setting input and output impedances
AssigneeFujitsu Limited
InventorsMasanori Ueda, Gou Endoh, Osamu Kawachi, Yoshiro Fujiwara
Life of this patent
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Abstract
A surface acoustic wave device supported by a package body. At least one surface acoustic wave element having interdigital electrodes disposed on a propagation path of a surface acoustic wave on the piezoelectric substrate. These interdigital electrodes include an input-side interdigital electrode connected to a ground pad on the package body and an output-side interdigital electrode connected to another ground pad on the package body.
Claims3
A surface-acoustic-wave device, comprising:
- a package body supporting a piezoelectric substrate thereon;
- at least one surface-acoustic-wave element formed on the piezoelectric substrate, each of said surface-acoustic-wave elements including a plurality of interdigital electrodes disposed along a propagation path of a surface acoustic wave on the piezoelectric substrate, each of said plurality of interdigital electrodes including an input-side interdigital electrode and an output-side interdigital electrode, the input-side interdigital electrode being connected to a first ground pad provided on said package body and the output-side interdigital electrode being connected to a second ground pad provided on said package body, wherein said surface-acoustic-wave device forms a double-mode type filter;
- and
- a ground electrode formed on said package body where said piezoelectric substrate is supported, said ground electrode connecting said first ground pad to said second ground pad,
- wherein the surface-acoustic-wave device further includes a conductive cap protecting the piezoelectric substrate, said conductive cap being electrically connected to said ground electrode on said package body.
2 more elements
A surface-acoustic-wave device, comprising:
- a package body supporting a piezoelectric substrate thereon;
- at least one surface-acoustic-wave element formed on the piezoelectric substrate, each of said surface-acoustic-wave elements including a plurality of interdigital electrodes disposed along a propagation path of a surface acoustic wave on the piezoelectric substrate, each of said plurality of interdigital electrodes including an input-side interdigital electrode and an output-side interdigital electrode, the input-side interdigital electrode being connected to a first ground pad provided on said package body and the output-side interdigital electrode being connected to a second ground pad provided on said package body, wherein said surface acoustic-wave device forms a double-mode type filter;
- and
- a ground electrode formed on said package body where said piezoelectric substrate is supported, said ground electrode connecting said first ground pad to said second ground pad, wherein the surface-acoustic-wave device further includes a conductive cap protecting the piezoelectric substrate, wherein the conductive cap is electrically connected to either the first or second ground pad.
1 more element
Dependencies are inferred from the claim text.