EP0817302A2 - Verfahren und Herstellung von Elektroden eines dielektrischen Filters - Google Patents

Verfahren und Herstellung von Elektroden eines dielektrischen Filters Download PDF

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Publication number
EP0817302A2
EP0817302A2 EP97304118A EP97304118A EP0817302A2 EP 0817302 A2 EP0817302 A2 EP 0817302A2 EP 97304118 A EP97304118 A EP 97304118A EP 97304118 A EP97304118 A EP 97304118A EP 0817302 A2 EP0817302 A2 EP 0817302A2
Authority
EP
European Patent Office
Prior art keywords
concave portions
conductors
forming
ceramic block
open end
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97304118A
Other languages
English (en)
French (fr)
Other versions
EP0817302A3 (de
Inventor
Seigo Hino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Publication of EP0817302A2 publication Critical patent/EP0817302A2/de
Publication of EP0817302A3 publication Critical patent/EP0817302A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P11/00—Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
    • H01P11/007—Manufacturing frequency-selective devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/201—Filters for transverse electromagnetic waves
    • H01P1/205—Comb or interdigital filters; Cascaded coaxial cavities
    • H01P1/2056—Comb filters or interdigital filters with metallised resonator holes in a dielectric block

Definitions

  • the present invention relates to a method of forming electrodes of a dielectric filter comprising a plurality of resonators disposed in parallel.
  • dielectric filters in which inner surfaces of through-holes of a dielectric ceramic block are coated with inner conductors so as to form a plurality of resonators in parallel, and the outer surface of the dielectric ceramic block is coated with an outer conductor except for the open end surface to which the through-holes are opened.
  • auxiliary conductors extend from the edges of open ends of, for example, two adjacent resonators such that an isolation gap is formed between facing edges of the auxiliary conductors for inter-stage capacitance coupling of the resonators.
  • input/output pads are formed on a side surface at positions facing the open ends of the resonators such that the input/output pads are electrically insulated from the outer conductor.
  • extension conductors are extended from the input/output pads toward the open end surface, so that isolation gaps are formed between the extension conductors and the auxiliary conductors. As a result, the input/output pads are connected to the resonators through the capacitances of the isolation gaps.
  • various kinds of conductor pattern are formed.
  • the above-described conductor pattern is formed by applying an electrode-forming material into a desired shape or pattern through use of screen pattern printing.
  • use of the screen pattern printing causes generation of blur at the boundary of the pattern or patchiness due to variation in the concentration of ink.
  • positioning of a screen is inadequate, the position of the conductor pattern relative to the block changes slightly, resulting in positional deviation.
  • the characteristics of resulting filters greatly vary, requiring a step of adjusting the characteristics, thus leading to increased production time, difficulty in mass-production, and a low yield.
  • an object of the present invention is to provide an improved method of forming electrodes of a dielectric filter in which the electrodes can be formed stably in a desired pattern.
  • the present invention provides an improved method of forming electrodes of a dielectric filter in which inner surfaces of through-holes of a dielectric ceramic block are coated with inner conductors so as to form a plurality of resonators in parallel; the outer surface of the dielectric ceramic block is coated with an outer conductor except for the open end surface to which the through-holes are opened; auxiliary conductors are formed on the open end surface of the dielectric filter such that they are connected to the inner conductors of the respective resonators; and input/output pads are formed on a side surface at positions facing the open ends of outermost resonators such that the input/output pads are electrically insulated from the outer conductor.
  • the method comprises the steps of: forming a ceramic block having through holes and concave portions, the positions and planar shapes of the concave portions corresponding to the positions and planar shapes of the auxiliary conductors to be formed on the open end surface of the ceramic block; forming an electrode layer over the entire open end surface; and grinding the open end surface to a depth smaller than the depth of the concave portions so as to leave the electrode layer within only the concave portions.
  • extension conductors are formed to extend from the input/output pads toward the open end surface
  • concave portions having planar shapes corresponding to the shapes of the respective extension conductors are formed at positions corresponding to the positions of the respective extension conductors, in a manner similar to the case of the auxiliary conductors.
  • the electrode layer forming step and the grinding step are carried out.
  • the shapes of the auxiliary conductors and/or extension conductors can be defined accurately by the concave portions. Accordingly, unlike the case of screen printing, neither blur nor patchiness occurs, thereby enabling stable pattern formation.
  • the above-described concave portions may be formed through press forming performed simultaneously with formation of the peripheral shape of the block.
  • the concave portions since the positions and shapes of the concave portions are defined by dies, the concave portions can be formed with high accuracy and can be formed at desired positions with improved reproducibility.
  • the above-described concave portions may be formed by milling or the like after the ceramic block is sintered.
  • the input/output coupling capacitances and the inter-stage coupling capacitance become constant, so that dielectric filters having stable filter characteristics can be obtained.
  • FIGS. 1 and 2 show a two-stage type dielectric filter 1 having two resonators 3.
  • the dielectric ceramic block 2 of the filter 1 is made of a titanium oxide ceramic and substantially has the shape of a rectangular prism.
  • the resonators 3 are formed parallel to each other.
  • the resonators 3 are formed by coating the through-holes 4 with inner conductors 5, and the outer surface of the dielectric ceramic block 2 is coated with an outer conductor 7 except for an open end surface 8 to which the through-holes 4 are opened.
  • the outer conductor 7 serves as a shield electrode.
  • the resonators 3 have a length corresponding to ⁇ /4, where ⁇ is a resonant frequency.
  • auxiliary conductors 6 for inter-stage coupling extend from the open ends of the two adjacent resonators 3 such that auxiliary conductors 6 for inter-stage coupling are connected to the inner conductors 5 of the through-holes 4.
  • the resonators 3 are coupled with each other through the capacitance C 1 (see FIG. 4) of an isolation gap g 1 formed between the auxiliary conductors 6 for inter-stage coupling.
  • input/output pads 9 are formed on a side surface of the dielectric ceramic block 2 at positions facing the open ends of the resonators 3 such that the input/output pads 9 are electrically insulated from the outer conductor 7.
  • the input/output pads 9 enable electrical connection with electrical paths on a printed circuit board.
  • Extension conductors 10 are extended from the input/output pads 9 toward the open end surface so that isolation gaps g 2 are formed between the extension conductors 10 and the auxiliary conductors 6.
  • the input/output pads 9 are connected to the auxiliary conductors 6 through the capacitances Co of the isolation gaps g 2 (see FIG. 4).
  • the input/output pads 9 are formed such that they face the outermost resonators.
  • the auxiliary conductors 6 and the extension conductors 10 are formed through the method illustrated in FIGS. 3A - 3C.
  • concave portions 20a' and 20b' are formed in the open end surface 8' of the green block 2' at positions corresponding to the positions of the respective auxiliary conductors 6 and the respective extension conductors 10 to be formed on the open end surface 8 of the dielectric ceramic block 2.
  • the concave portions 20a' and 20b' have planar shapes corresponding to the shapes of the respective auxiliary conductors 6 and the respective extension conductors 10.
  • the open end surface 8 is subjected to grinding operation.
  • This grinding operation is carried out such that the grinding depth is less than the depth of the concave portions 20a and 20b (see line I-I in FIG. 3B).
  • the electrode layer 21 covering the open end surface 8 of the dielectric ceramic block 2 is removed such that the electrode layer 21 in the concave portions 20a and 20b are left unground.
  • the portions of the electrode layer 21 remaining in the concave portions 20a and 20b serve as the auxiliary conductors 6 and the extension conductors 10, respectively.
  • square-C-shaped exposed portions 23 are formed through partial removal of the outer conductor 7.
  • the auxiliary conductors 6 and the extension conductors 10 formed in the concave portions 20a and 20b are defined by the concave portions 20a and 20b, so that the auxiliary conductors 6 and the extension conductors 10 can be formed with high accuracy and at desired positions.
  • the conductor pattern does not cause patchiness, and the boundary of the pattern becomes clearer and does not become blurred. Since none of blur, patchiness, and positional shift occurs, the pattern can be formed with high accuracy, thereby enabling the stable generation of capacitance coupling.
  • the concave portions 20a' and 20b' are formed through press forming performed simultaneously with formation of the peripheral shape of the green block 2', no additional step is required, so that the manufacture of the dielectric filter can be facilitated.
  • the above-described manufacturing method may be modified such that after the press forming of the green block 2', the concave portions 20a' and 20b' are formed by milling or the like simultaneously with the formation of the through-holes 4'.
  • the auxiliary conductors 6 for inter-stage coupling can be formed without causing blur or patchiness.
  • concave portions 20a' and 20b' can be formed by milling or the like after the green block 2' is sintered.
  • the extension conductors 10 extended from the input/output pads 9 are not necessarily required, and the auxiliary conductors 6 may be extended further such that the auxiliary conductors 6 are coupled directly with the input/output pads 9 via insulation gaps g 2 .
  • the concave portions are formed at only locations where the auxiliary conductors are to be formed.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
EP97304118A 1996-07-03 1997-06-12 Verfahren und Herstellung von Elektroden eines dielektrischen Filters Withdrawn EP0817302A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP193914/96 1996-07-03
JP19391496A JPH1022710A (ja) 1996-07-03 1996-07-03 誘電体フィルタの電極形成方法

Publications (2)

Publication Number Publication Date
EP0817302A2 true EP0817302A2 (de) 1998-01-07
EP0817302A3 EP0817302A3 (de) 1998-11-18

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP97304118A Withdrawn EP0817302A3 (de) 1996-07-03 1997-06-12 Verfahren und Herstellung von Elektroden eines dielektrischen Filters

Country Status (2)

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EP (1) EP0817302A3 (de)
JP (1) JPH1022710A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0997964A2 (de) * 1998-10-29 2000-05-03 Murata Manufacturing Co., Ltd. Dielektrisches Filter, dielektrischer Duplexer und Kommunikationsgerät
FR2804795A1 (fr) * 2000-01-17 2001-08-10 Murata Manufacturing Co Filtre dielectrique, duplexeur dielectrique, systeme de communication et procede de fabrication de filtre dielectrique

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002158512A (ja) 2000-09-08 2002-05-31 Murata Mfg Co Ltd 誘電体共振器、誘電体フィルタ、誘電体デュプレクサ、および通信装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02185101A (ja) * 1989-01-12 1990-07-19 Alps Electric Co Ltd 誘電体フィルタの製造方法
JPH02260902A (ja) * 1989-03-31 1990-10-23 Kyocera Corp 誘電体同軸共振器及びその製造方法
JPH03190303A (ja) * 1989-12-19 1991-08-20 Matsushita Electric Ind Co Ltd 誘電体同軸共振器
EP0635897A1 (de) * 1993-07-23 1995-01-25 NGK Spark Plug Co. Ltd. Dielektrisches Filter
JPH0786807A (ja) * 1993-07-23 1995-03-31 Sony Chem Corp 誘電体フィルタ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02185101A (ja) * 1989-01-12 1990-07-19 Alps Electric Co Ltd 誘電体フィルタの製造方法
JPH02260902A (ja) * 1989-03-31 1990-10-23 Kyocera Corp 誘電体同軸共振器及びその製造方法
JPH03190303A (ja) * 1989-12-19 1991-08-20 Matsushita Electric Ind Co Ltd 誘電体同軸共振器
EP0635897A1 (de) * 1993-07-23 1995-01-25 NGK Spark Plug Co. Ltd. Dielektrisches Filter
JPH0786807A (ja) * 1993-07-23 1995-03-31 Sony Chem Corp 誘電体フィルタ

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 14, no. 461 (E-987), 5 October 1990 & JP 02 185101 A (ALPS ELECTRIC CO LTD), 19 July 1990 *
PATENT ABSTRACTS OF JAPAN vol. 15, no. 4 (E-1020), 8 January 1991 & JP 02 260902 A (KYOCERA CORP), 23 October 1990 *
PATENT ABSTRACTS OF JAPAN vol. 15, no. 448 (E-1133), 14 November 1991 & JP 03 190303 A (MATSUSHITA ELECTRIC IND CO LTD), 20 August 1991 *
PATENT ABSTRACTS OF JAPAN vol. 95, no. 6, 31 July 1995 & JP 07 086807 A (SONY CHEM CORP), 31 March 1995 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0997964A2 (de) * 1998-10-29 2000-05-03 Murata Manufacturing Co., Ltd. Dielektrisches Filter, dielektrischer Duplexer und Kommunikationsgerät
EP0997964A3 (de) * 1998-10-29 2001-09-05 Murata Manufacturing Co., Ltd. Dielektrisches Filter, dielektrischer Duplexer und Kommunikationsgerät
US6549095B2 (en) 1998-10-29 2003-04-15 Murata Manufacturing Co. Ltd. Dielectric filter, dielectric duplexer, and communication apparatus
EP1947731A1 (de) * 1998-10-29 2008-07-23 Murata Manufacturing Co., Ltd. Dielektrisches Filter, dielektrischer Duplexer und Kommunikationsvorrichtung
FR2804795A1 (fr) * 2000-01-17 2001-08-10 Murata Manufacturing Co Filtre dielectrique, duplexeur dielectrique, systeme de communication et procede de fabrication de filtre dielectrique
US6504455B2 (en) 2000-01-17 2003-01-07 Murata Manufacturing Co., Ltd. Dielectric filter, dielectric duplexer, communication system, and method of producing dielectric filter

Also Published As

Publication number Publication date
EP0817302A3 (de) 1998-11-18
JPH1022710A (ja) 1998-01-23

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