Patents by Inventor Youhei Ishikawa

Youhei Ishikawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5159294
    Abstract: A non-reciprocal circuit element which includes a case, a circuit element main body provided in the case including central conductors disposed to intersect each other in an electrically insulated state and matching circuitry, and ferrite members disposed to confront the central conductors so as to impress a d.c. magnetic field. The case is made of an insulative resin, and covered by electrode films formed to constitute at least part of the circuit element main body and terminals for the central conductors.
    Type: Grant
    Filed: February 28, 1991
    Date of Patent: October 27, 1992
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Takekazu Okada, Keiji Okamura, Takashi Kawanami
  • Patent number: 5132651
    Abstract: A filter apparatus in accordance with the present invention comprises, for example, a band-pass filter and a plurality of band-stop filters connected as the post-stage to the band-pass filter. The band-pass filter transmits a band containing a desired frequency band, and the band-stop filters attenuate undesirable frequency bands. Another filter apparatus in accordance with the present invention comprises, for example, a first band-pass filter, a circulator connected to the first band-pass filter, and second band-pass filters connected to the circulator. The first band-pass filter transmits a band containing a desired frequency band to the circulator, and the second band-pass filters transmit undesirable frequency bands and reflect the desire frequency band to the circulator. The desired frequency band is outputted from this circulator. Still another filter apparatus in accordance with the present invention comprises, for example, a circulator and a band-pass filter connected to the circulator.
    Type: Grant
    Filed: June 11, 1990
    Date of Patent: July 21, 1992
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Jun Hattori, Toshio Nishikawa
  • Patent number: 5119034
    Abstract: A method of measuring dielectric material constants, which includes steps of forming a dielectric resonator by providing a plurality of coupling terminals for input and output of signals, on a shield case, with a dielectric sample being disposed within the shield case, constituting an oscillation circuit together with the dielectric resonator by connecting a positive feed-back circuit including an amplification circuit, between the signal output coupling means and the signal output coupling means, and measuring variation in an oscillation frequency of the oscillation circuit by heating the dielectric sample through injection of a high frequency power into the particular coupling terminal, so as to obtain a specific material constant of the dielectric sample based on the variation of the oscillation frequency, and, also a measuring device employed for effecting the measuring method.
    Type: Grant
    Filed: July 9, 1990
    Date of Patent: June 2, 1992
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Hidekazu Wada, Jun Hattori, Hiroyuki Kubo, Taiyo Nishiyama
  • Patent number: 5097236
    Abstract: A parallel connection multi-stage band-pass filter including an input terminal and an output terminal for signals, a plurality of resonators respectively having resonator frequencies different from and close to one another which are electrically connected in parallel to each other between said input and output terminals.
    Type: Grant
    Filed: May 1, 1990
    Date of Patent: March 17, 1992
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Kikuo Wakino, Toshio Nishikawa, Youhei Ishikawa, Koichi Takehara, Toru Tanizaki
  • Patent number: 5049842
    Abstract: This dielectric resonator comprises a cylindrical hollow case made of metal, a cylindrical hollow dielectric resonator element which is fixed and held in the case, and a dielectric tuning unit which is inserted into or withdrawn from a hollow portion of the dielectric resonator element. The hollow portion of the dielectric resonator element is formed by at least one, or a plurality of, cutout portions which extend along respective radii of the cylindrical dielectric resonator. In this dielectric resonator, the overall effective dielectric constant as a whole can be varied by inserting the tuning unit into or withdrawing it from the hollow portion of the dielectric resonator element. When the tuning unit is withdrawn from the hollow portion of the dielectric resonator element, part of an electric field path at the dielectric resonator element is interrupted by the cutout portions.
    Type: Grant
    Filed: November 15, 1988
    Date of Patent: September 17, 1991
    Assignee: Murata Mfg. Co., Ltd.
    Inventors: Youhei Ishikawa, Hidekazu Wada, Kouichi Takehara, Toru Tanizaki, Shigeji Arakawa, Shinichi Kunioka
  • Patent number: 4996506
    Abstract: A band elimination filter which includes at least one or more TM-mode dielectric resonators each including a ceramic casing with an electrically conductive film formed over its inner surface or outer surface, and a dielectric column disposed in a cavity in the ceramic casing, and an electrode provided on the ceramic casing, out of contact with the electrically conductive film, with transmission lines being connected to the electrode.
    Type: Grant
    Filed: September 28, 1989
    Date of Patent: February 26, 1991
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Toshiro Hiratsuka, Hirotsugu Abe, Hisashi Takagaki, Sadao Yamashita
  • Patent number: 4942377
    Abstract: A dielectric resonating device comprises a conductive case, a bar-shaped dielectric resonator body located in the case, exciting means for exciting the dielectric resonator body, and at least one plate located between the case and the dielectric resonator body, forming at least two resonators of said device. An inner peripheral end of the plate is fixed to the dielectric resonator body. An outer peripheral end of the plate is located to face the case and define therewith a gap for coupling adjustment between the two resonators.The exciting means has electrodes connected to both ends of the dielectric resonator body, and input and output connectors fixed to the electrodes. The electrodes each have the shape of a flat plate and they are located with a gap between them and the case.
    Type: Grant
    Filed: May 23, 1988
    Date of Patent: July 17, 1990
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Kikuo Tsunoda, Toshiro Hiratsuka, Hirotsugu Abe
  • Patent number: 4916417
    Abstract: A filter employing Triplate type microstripline as the base element comprises first and second dielectric substrates which are superposed with each other so as to hold a resin sheet therebetween, and are contained in a metal case. The respective dielectric substrates are provided on outer major surfaces with ground electrodes to be electrically connected with the metal case. Resonance electrodes are provided on inner major surfaces of the respective dielectric substrates to be electrically connected with relating ground electrodes through end surfaces of the dielectric substrates. The resin sheet holds metal pins passing through the same along the direction of thickness thereof, so that the respective resonance electrodes of the first and second dielectric substrates are electrically connected with each other by the metal pins.
    Type: Grant
    Filed: August 22, 1989
    Date of Patent: April 10, 1990
    Assignee: Murata Mfg. Co., Ltd.
    Inventors: Youhei Ishikawa, Jun Hattori, Hideyuki Kato
  • Patent number: 4902991
    Abstract: A radio frequency signal combining/sorting device which includes a plurality of filters, and a duplexer device connected to one side of input/output sides of each of the filters for combining/sorting signals, and is characterized in that there is provided a coupling device formed at the input/output ends of the filter connected side of the duplexer means device, with the filters being formed, at their side connected to the duplexer device, with openings for receiving the coupling device.
    Type: Grant
    Filed: March 10, 1988
    Date of Patent: February 20, 1990
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Hidekazu Wada, Koichi Takehara, Shigeji Arakawa, Toru Tanizaki
  • Patent number: 4839773
    Abstract: In a dielectric filter which has a plurality of dielectric resonators of a TM.sub.010 mode or its modified mode, each dielectric resonator has one dielectric solid body disposed in series with a metallic case having top and bottom faces and at least one side face. A conductive film is provided to form the actual current paths on the surface of the ceramic case, and a conductive plate is provided between the dielectric resonators to electrically connect the resonators with each other, whereby a given electro-magnetic combination is caused between the adjacent dielectric resonators so as to provide a dielectric filter having given characteristics.
    Type: Grant
    Filed: June 22, 1988
    Date of Patent: June 13, 1989
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Kikuo Tsunoda, Toshiro Hiratsuka, Hirotsugu Abe
  • Patent number: 4821006
    Abstract: The dielectric resonator apparatus is characterized in that electric walls exist on one plane or two including the central axis of the electromagnetic field distribution in the using mode of a dielectric resonator, a dielectric resonator with either of dielectrics between the electric wall being removed in shape is provided by plurality, an equivalent axis is common to the central axis of each of the dielectric resonators, with the dielectric resonators being inductively coupled in the axial direction. A dielectric resonator which prevents the current from being concentrated on the central axis of the electromagnetic field distribution, is collectively smaller in the Joule loss and is higher in Q. The dielectric resonator of the present invention is characterized in that the dielectric close to the central axis is removed, wherein electric walls exist on one plane or two including the central axis of the electromagnetic field distribution in a dielectric resonator using, for instance, a TE.sub.01.delta.
    Type: Grant
    Filed: January 14, 1988
    Date of Patent: April 11, 1989
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Kikuo Tsunoda, Toshiro Hiratsuka, Hirotsugu Abe
  • Patent number: 4816788
    Abstract: A high frequency band-pass filter which includes a single resonator or a plurality of resonators adapted to pass a high frequency signal of a predetermined frequency band region, and an active element device electrically coupled with one or the plurality of the resonators so as to present a negative resistance when the resonator is in a resonant state.
    Type: Grant
    Filed: June 30, 1987
    Date of Patent: March 28, 1989
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Hiroaki Tanaka
  • Patent number: 4740765
    Abstract: A dielectric filter includes a single block made of dielectric material having three or more through holes in which an inner conductor is deposited to define three or more dielectric resonators coupled in a cascade manner. A reactance coupling arrangement is provided for coupling two spaced dielectric resonators with at least one dielectric resonator between them being skipped. By selecting the value of the reactance coupling arrangement, it is possible to provide a filter having a frequency characteristic in a desired format, including at least one pole at a selected point in an attenuation region thereof, without any increase in the number of stages of the dielectric resonators.
    Type: Grant
    Filed: September 29, 1986
    Date of Patent: April 26, 1988
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Sadao Yamashita, Kikuo Tsunoda, Toshiro Hiratsuka, Kazuyoshi Miyawaki
  • Patent number: 4733208
    Abstract: A dielectric filter comprises a cubic dielectric block in which a plurality of holes arranged in the longitudinal direction are formed vertically therethrough. On outer surfaces of the dielectric block, an outer conductor is formed except on the upper surface. On inner surfaces of a plurality of the holes, inner conductors constituting resonance elements in cooperation with the outer conductor are formed. Grooves are formed in the dielectric block between the adjacent resonance elements. Thereby, impedance of a part of a lengthwise direction of at least one of the adjacent resonance elements differs from that of the other part, at least in one of the even and odd modes. In order to have different impedances, notches may be formed on the dielectric block between the adjacent inner conductors or large and small diameter portions may be formed in the holes or further the two methods may be combined.
    Type: Grant
    Filed: August 16, 1985
    Date of Patent: March 22, 1988
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Kikuo Tsunoda, Toshiro Hiratsuka
  • Patent number: 4728913
    Abstract: A dielectric resonator comprises a shield electrode defining a resonant space and cylindrical dielectric resonator element disposed and supported fixedly in the resonant space, to which an input and output are coupled. Into the hollow portion of the dielectric resonator element, a tuning unit made of a dielectric material is inserted so as to be displaceable in an axial direction therein. The tuning unit is coupled to a supporting axis which is displaceable axially, thus causing the tuning unit to displace in that direction. A resonance frequency of the dielectric resonator varies as the tuning unit displaces.
    Type: Grant
    Filed: January 17, 1986
    Date of Patent: March 1, 1988
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Hidekazu Wada, Kouichi Takehara
  • Patent number: 4727342
    Abstract: A dielectric resonator employing the TM mode as its resonance mode, which is provided with a dielectric base plate on which an electronic circuit is formed and a pair of electrodes formed in face-to-face relation to each other on respective major surfaces of the dielectric base plate. A plurality of through-holes are defined between the pair of electrodes on their circumferential portions and both of the electrodes are connected with each other by way of conductive material formed on the inner surfaces of the through-holes.
    Type: Grant
    Filed: September 22, 1986
    Date of Patent: February 23, 1988
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Youhei Ishikawa, Jun Hattori
  • Patent number: 4721931
    Abstract: A stripline filter includes a cylindrical substrate made of a dielectric material and having inner and outer surfaces with opposite ends thereof opened. A ground electrode is deposited on the inner surface, and on the inner surface, interdigitated electrodes are deposited. Alternately, the ground electrode may be deposited on the outer surface, and the interdigitated electrodes may be deposited on the inner surface. Thus, the stripline filter can be arranged in a compact size. Also, the ground electrode provided on the outer surface prevents electromagnetic waves generated from the interdigitated electrodes from being emitted out.
    Type: Grant
    Filed: April 30, 1987
    Date of Patent: January 26, 1988
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Toshio Nishikawa, Youhei Ishikawa, Jun Hattori, Hideyuki Kato
  • Patent number: 4706052
    Abstract: A dielectric resonator provided with a plurality of dielectric resonator units which are combined into one unit, with a boundary being formed between adjacent dielectric resonator units, a connecting material for rigidly connecting said adjacent dielectric resonator units to each other, a support member for placing said dielectric resonator units thereon, a metallic conductive case accommodating said dielectric resonator units on said support member therein, and input and output members for electrical connection of said dielectric resonator with an external circuit, whereby a resonant frequency of spurious mode is shifted into a frequency zone higher than a resonant point by causing said spurious mode to pass through boundary surfaces or layers.
    Type: Grant
    Filed: December 6, 1985
    Date of Patent: November 10, 1987
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Jun Hattori, Youhei Ishikawa
  • Patent number: 4692727
    Abstract: A dielectric resonator device includes a casing for defining a chamber in which a dielectric resonator and a piezoelectric frequency adjusting unit are provided. A portion of the piezoelectric frequency adjusting unit is located adjacent the dielectric resonator. By the voltage applied to the piezoelectric frequency adjusting unit, the piezoelectric frequency adjusting unit changes its shape thereby changing the distance between the portion of the piezoelectric frequency adjusting unit and the dielectric resonator. Thus, the resonance frequency of the dielectric device can be controlled.
    Type: Grant
    Filed: June 3, 1986
    Date of Patent: September 8, 1987
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Kikuo Wakino, Hiroshi Tamura, Youhei Ishikawa
  • Patent number: 4639699
    Abstract: A dielectric resonator is disclosed which includes a case having a resonator main body portion, an upper lid and a lower lid. Inside the case is a cylindrical dielectric material. The case is formed of a dielectric material having the same coefficient of linear expansion as the cylindrical dielectric material. In one embodiment, main body portion comprises a dielectric case side portion with the cylindrical dielectric material disposed concentrically in a concavity defined by the case side portion, with the cylindrical dielectric material being integrally coupled to the dielectric case side portion by four connecting portions. More specifically, in this embodiment, the case side portion of the main body portion and the cylindrical portion are simultaneously and integrally formed of the same dielectric material. A conductive film is formed to enclose a region surrounding the cylindrical dielectric material.
    Type: Grant
    Filed: September 30, 1983
    Date of Patent: January 27, 1987
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Toshio Nishikawa, Youhei Ishikawa, Hidekazu Wada