Patent US2807584A successfully refreshed from Google Patents.
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EP0100503A2
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High frequency narrow-band pass multi-mode filter
Assignee: Toyo Communication Equipment Co Ltd
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Filing: 1983-07-23
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Granted: —
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Expires: 2003-07-23
Abstract
Abstract A high frequency narrow-band pass multi-mode filter in constructed in such manner that SAW of SSBW resonators are closely disposed to each other on a single piezo-electric substrate to generate different vibration modes of different resonance frequencies, conditions that the resonators are acoustically coupled to each other to cause these vibration modes, are experimentally found, and the above conditions are satisfied by the filter. In order to reduce the ohmic loss of a very narrow common bus bar, the number of strip pairs of electrode in both interdigital transducers (hereinafter referred to as IDT) is minimized and instead reflectors are provided on the both sides of said TDTs to compensate for the reduction of its Q value. A part of the bus bar for the IDT electrodes is formed integral with some or all of gratings of the reflectors, whereby the connecting positions of the grating electrodes with respect to lead terminals can be positioned with a high freedom.
Inventors
- 👤 Yuzo Toyo Comm. Equipment Co. Ltd. Nakazawa
- 👤 Kazuo Toyo Communication Equipment Co. Ltd. Ono
- 👤 Masaki Toyo Comm. Equipment Co. Ltd. Tanaka
- 👤 Takao Toyo Comm. Equipment Co. Ltd. Morita
- 👤 Takefumi Toyo Comm. Equipment Co. Ltd. Kurosaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:23
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/64; H03H9/6423; H03H9/6433; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02944; H03H9/644; H03H9/6456; H03H9/6459; H03H9/6463
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
In a multi-mode SAW filter wherein a plurality of interdigital transducer electrodes each vibrating at the same resonance frequency are arranged on a piezo-electric quartz crystal substrate in mutually parallel and closed relations and in directions perpendicular to propagating directions of SAWs excited by said interdigital transducer electrodes to utilize the resonance frequencies of different vibration modes generated by acoustic coupling between the waves propagating in the directions perpendicular to said SAW propagating directions; a high frequency narrow-band pass multi-mode filter being characterized in that a width of an acoustic aperture w and a gap between the acoustic apertures g satisfy relations w ≦ 20λ and g ≦ 6X preferably g < 3X where X is the wavelength of the excited SAW.
Claim 2
Dependent Claim
122 words
In a multi-mode SAW filter wherein a plurality of interdigital transducer electrodes each vibrating at the same resonance frequency are arranged on a piezo-electric quartz crystal substrate in mutually parallel and closed relations and in directions perpendicular to propagating directions of SAWs excited by said interdigital transducer electrodes to utilize the resonance frequencies of different vibration modes generated by acoustic coupling between the waves propagating in the directions perpendicular to said SAW propagating directions; a high frequency narrow-band pass multi-mode filter being characterized in that a width of an acoustic aperture w and a gap between the acoustic apertures g satisfy relations w ≦ 20λ and g ≦ 6X preferably g < 3X where X is the wavelength of the excited SAW.
Claim 3
Dependent Claim
24 words
A filter as set forth in claim 1, wherein a wave excited by said interdigital transducer electrodes is a surface skimming bulk wave (SSBW).
Claim 4
Dependent Claim
45 words
A high frequency narrow-band pass multi-mode filter of multi-section type, wherein said multi-mode filter set forth in claim 1 or 2 forms a unit section and a plurality of said unit sections are connected in a tandem manner a desired shape factor and guaranteed attenuation.
Claim 5
Dependent Claim
30 words
A filter as set forth in claims 1 to 3, wherein reflectors are provided on both sides of said interdigital transducer electrodes to reflect the SAW excited by said electrodes.
Claim 6
Dependent Claim
51 words
A filter as set forth in claim 4, wherein a part of the common bus bar for said electrodes is formed integral with some or all of gratings of the reflectors, whereby the connecting positions of the strips of said grating with lead terminals can be positioned with a high freedom.
Claim 7
Dependent Claim
75 words
A filter as set forth in claim 5, wherein the common bus bar for said interdigital transducer electrodes is formed integral with the gratings of said reflectors and connected to the gratings, and said common bus bar is grounded, whereby connecting positions of said common bus bar with respect to the lead terminals are positioned with a high freedom and the ohmic loss of said common bus bar and thus the filter loss is reduced.
Claim 8
Dependent Claim
28 words
A filter as set forth in claim 4, 5 or 6, wherein waves excited by said interdigital transducer electrodes are waves other than SAW excitable by said electrodes.
Claim 9
Dependent Claim
43 words
A filter as set forth in claim 4, wherein the common bus bar for said electrodes is extended across the gratings of said reflectors and not connected to the gratings, and the width of said bus bar in the gratings is gradually increased.
Claim 10
Dependent Claim
55 words
A filter as set forth in claim 4, wherein the common bus bar for said electrodes is extended across the grating of said reflectors and connected to the gratings, the width of said bus bar in the grating is gradually increased, and both ends of the strips of the grating of the reflectors are open.
Claim 11
Dependent Claim
52 words
A filter as set forth in claim 4, wherein said common bus bar for said resonators is connected to lead patterns, said patterns are provided in place between the interdigital transducers and said reflectors, and extended from position connected with said common bus bar to a peripheral edge of said piezo-electric substrate.
Claim 12
Dependent Claim
55 words
A filter as set forth in claim 4, wherein the common bus bar for said electrodes is extended across grooves or metal strips of said reflectors and connected or not connected to said grooves or strips, and the width of the common bus bar is increased gradually_in the grooves or strips toward outer sides thereof.
References Cited (Backward Citations)
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