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US 7,304,553 B2Granted
Filter with acoustically coupled resonators
AssigneeEpcos AG
InventorsThomas Bauer, Ken-ya Hashimoto, Ulrike Roesler, Werner Ruile, Veit Meister, Heide Kuhrau, Michael Jakob
Life of this patent
Estimating the term…
Abstract
A component operating with surface-proximal acoustic waves, in particular a filter with novel structure, has interdigital transducers arranged in serial and parallel branches, which are acoustically coupled with one another in different configurations. The component provides a loss-poor filter with simultaneously space-saving arrangement of the filter elements.
Claims40
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said at least one serial branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- both coupled interdigital transducers being arranged in a serial branch.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- at least two serial interdigital transducers following in succession in circuit in the serial branch are arranged next to one another transverse to the propagation direction of the acoustic surface wave to form a first electrical cascade;
- another at least two interdigital transducers following in succession in circuit in the serial branch or in the parallel branch and arranged next to one another to form a second electrical cascade;
- two of the interdigital transducers coupled to one another are in a same cascade;
- and
- the interdigital transducers of the first electrical cascade being acoustically coupled with corresponding ones of the interdigital transducers of the second cascade.
13 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- at least three serial interdigital transducers arranged next to one another are part of a cascade, in which the three interdigital transducers are acoustically coupled, in which both outer interdigital transducers are circuited parallel to one another and respectively in series relative to a center interdigital transducer of the three interdigital transducers.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- two parallel interdigital transducers are provided that are part of a DMS filter.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- all serial interdigital transducers are arranged in a common serial track and all parallel interdigital transducers are arranged in a common parallel track.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in the propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- the two interdigital transducers acoustically coupled with one another exhibit a same finger period, however are displaced against each other by an amount Δx, with −0.25<Δx/λ<0.25, whereby λ is an acoustic wavelength at a center frequency of the component.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on a surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting an input and an output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- additional elements selected from one-port resonators and DMS tracks are connected serially to the parallel interdigital transducers.
10 more elements
A component operating with surface-proximal acoustic waves, said component comprising:
- at least three interdigital transducers being arranged on surface of a piezoelectric substrate, said interdigital transducers being respectively provided with a first and a second electrical connection and being electrically circuited with one another via said first and second electrical connections, so that the interdigital transducers are selected from serial and parallel interdigital transducers;
- at least one serial interdigital transducer being arranged in at least one serial branch serving as a signal path, said branch connecting the input and the output of the component and in which all elements contained therein are electrically connected in series;
- at least one parallel branch in which is arranged a parallel interdigital transducer being connected parallel thereto against a reference potential;
- at least one of the serial or parallel interdigital transducers being arranged in series with an additional interdigital transducer in a propagation direction of the acoustic wave, so that both interdigital transducers are acoustically coupled with one another, so that the transducers coupling with each other differ from each other by at least one of the following features selected from a group consisting of:
- a) the interdigital transducers possessing a different aperture,
- b) the interdigital transducers possessing a different pitch,
- c) the interdigital transducers belong to different branches of the component,
- d) of the interdigital transducers, at least one is arranged in the serial branch and the transducers being not directly electrically connected with one another,
- e) the interdigital transducers comprising a different number of interdigital electrode fingers,
- f) the interdigital transducers exhibiting a different metallization ratio, and
- g) the interdigital transducers being weighted and exhibiting a different weighting;
- and
- both coupled interdigital transducers being arranged in a parallel branch.
10 more elements
Dependencies are inferred from the claim text.