Patents by Inventor Masafumi Shigaki
Masafumi Shigaki 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).
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Patent number: 7729129Abstract: In a package mounting structure for mounting a package on a case, wherein the package internally incorporates at least one of a high-frequency transistor, MIC and MMIC used in the microwave to millimeter-wave band, and a base thereof is formed of metal and serves as ground, an electrically conductive sheet having excellent thermal conductivity and exhibiting restorability and having a size identical with that of the base of the package is laid on the case at a package-bearing location, the package and sheet are fastened together by two or more screws, and the sheet is mounted on the case while it is pressed by a pressing force of 10 N/cm2 or greater owing to fastening.Type: GrantFiled: October 17, 2007Date of Patent: June 1, 2010Assignee: Fujitsu LimitedInventors: Masafumi Shigaki, Isao Nakazawa, Kazunori Yamanaka
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Patent number: 7495615Abstract: An antenna coupling module for electromagnetically coupling a planar antenna and a planar type oxide superconductive high frequency circuit not reducing the antenna effective area and sharply reducing the signal loss due to coupling, comprised of a planar antenna and a substrate forming a planar superconductive high frequency circuit arranged in a perpendicular direction with respect to the element surface of the planar antenna and having the planar antenna and the superconductive high frequency circuit electromagnetically coupled.Type: GrantFiled: March 3, 2004Date of Patent: February 24, 2009Assignee: Fujitsu LimitedInventors: Kazunori Yamanaka, Isao Nakazawa, Masafumi Shigaki
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Publication number: 20080144287Abstract: In a package mounting structure for mounting a package on a case, wherein the package internally incorporates at least one of a high-frequency transistor, MIC and MMIC used in the microwave to millimeter-wave band, and a base thereof is formed of metal and serves as ground, an electrically conductive sheet having excellent thermal conductivity and exhibiting restorability and having a size identical with that of the base of the package is laid on the case at a package-bearing location, the package and sheet are fastened together by two or more screws, and the sheet is mounted on the case while it is pressed by a pressing force of 10 N/cm2 or greater owing to fastening.Type: ApplicationFiled: October 17, 2007Publication date: June 19, 2008Applicant: FUJITSU LIMITEDInventors: Masafumi Shigaki, Isao Nakazawa, Kazunori Yamanaka
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Patent number: 7379023Abstract: An antenna device includes a plane-type antenna element, a heat insulation container for blocking heat entering from the outside, the heat insulation container having a radio-wave window allowing a radio wave to pass therethrough, and housing the plane-type antenna element, a waveguide housed in the heat insulation container and arranged between the radio-wave window and an antenna pattern formation surface of the plane-type antenna element, and cooling means for cooling the plane-type antenna element. The waveguide is shaped and dimensioned so that the directivity of the plane-type antenna element is enhanced, and a superconducting film is used for the antenna pattern of the plane-type antenna element.Type: GrantFiled: June 16, 2006Date of Patent: May 27, 2008Assignee: Fujitsu LimitedInventors: Kazunori Yamanaka, Masafumi Shigaki, Isao Nakazawa
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Patent number: 7285429Abstract: In a package mounting structure for mounting a package on a case, wherein the package internally incorporates at least one of a high-frequency transistor, MIC and MMIC used in the microwave to millimeter-wave band, and a base thereof is formed of metal and serves as ground, an electrically conductive sheet having excellent thermal conductivity and exhibiting restorability and having a size identical with that of the base of the package is laid on the case at a package-bearing location, the package and sheet are fastened together by two or more screws, and the sheet is mounted on the case while it is pressed by a pressing force of 10 N/cm2 or greater owing to fastening.Type: GrantFiled: August 27, 2004Date of Patent: October 23, 2007Assignee: Fujitsu LimitedInventors: Masafumi Shigaki, Isao Nakazawa, Kazunori Yamanaka
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Patent number: 7283855Abstract: A dielectric waveguide which comprises a first single crystal magnesium oxide block having a surface of face (001), (100) or (010) and a first copper oxide superconducting film formed on the above-described surface in a c-axis crystal orientation perpendicular to the surface, and a method of production thereof are provided.Type: GrantFiled: August 26, 2003Date of Patent: October 16, 2007Assignee: Fujitsu LimitedInventors: Kazunori Yamanaka, Akihiko Akasegawa, Masafumi Shigaki, Isao Nakazawa
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Publication number: 20070001910Abstract: An antenna device includes a plane-type antenna element, a heat insulation container for blocking heat entering from the outside, the heat insulation container having a radio-wave window allowing a radio wave to pass therethrough, and housing the plane-type antenna element, a waveguide housed in the heat insulation container and arranged between the radio-wave window and an antenna pattern formation surface of the plane-type antenna element, and cooling means for cooling the plane-type antenna element. The waveguide is shaped and dimensioned so that the directivity of the plane-type antenna element is enhanced, and a superconducting film is used for the antenna pattern of the plane-type antenna element.Type: ApplicationFiled: June 16, 2006Publication date: January 4, 2007Applicant: FUJITSU LIMITEDInventors: Kazunori Yamanaka, Masafumi Shigaki, Isao Nakazawa
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Patent number: 6914483Abstract: A signal is sampled at a stage following a first amplifier circuit (12, 14, 16) and preceding a second amplifier circuit (20, 22), and the presence or absence of a signal is detected by a detector circuit (30). When the presence of a signal is detected, a gate bias circuit (32) switches a gate bias for FETs in the second amplifier circuit (20, 22) to a normal operating voltage value, and when the signal is no longer detected, the gate bias is switched to a voltage value that reduces power consumption, after a mask time has elapsed. In a distortion feedback-type high-frequency amplifier circuit, a means for cutting off a circuit portion for the adjustment of each of a distortion extracting circuit and an inverse distortion adding circuit is achieved by switching FET gate voltage so as to put the corresponding amplifier in a virtually cutoff condition.Type: GrantFiled: August 12, 2004Date of Patent: July 5, 2005Assignee: Fujitsu LimitedInventor: Masafumi Shigaki
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Patent number: 6859029Abstract: A monitoring system for high-frequency circuits which minimizes the insertion loss of additional monitoring circuits while requiring only a small space. An input coupler is placed at the input of a high-frequency circuit whose frequency response is to be monitored. The input coupler has a space where a given high-frequency probing signal can propagate, and it combines this propagating signal with a given electrical input signal. The combined signal is processed by the high-frequency circuit, and the resulting signal is supplied to an output coupler. The output coupler has a space for propagation of a high-frequency probing signal component contained in the received combined signal. The output coupler extracts this propagating signal component for the purpose of monitoring.Type: GrantFiled: July 24, 2003Date of Patent: February 22, 2005Assignee: Fujitsu LimitedInventors: Kazunori Yamanaka, Isao Nakazawa, Masafumi Shigaki, Manabu Kai
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Publication number: 20050029546Abstract: In a package mounting structure for mounting a package on a case, wherein the package internally incorporates at least one of a high-frequency transistor, MIC and MMIC used in the microwave to millimeter-wave band, and a base thereof is formed of metal and serves as ground, an electrically conductive sheet having excellent thermal conductivity and exhibiting restorability and having a size identical with that of the base of the package is laid on the case at a package-bearing location, the package and sheet are fastened together by two or more screws, and the sheet is mounted on the case while it is pressed by a pressing force of 10 N/cm2 or greater owing to fastening.Type: ApplicationFiled: August 27, 2004Publication date: February 10, 2005Inventors: Masafumi Shigaki, Isao Nakazawa, Kazunori Yamanaka
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Publication number: 20050012548Abstract: A signal is sampled at a stage following a first amplifier circuit (12, 14, 16) and preceding a second amplifier circuit (20, 22), and the presence or absence of a signal is detected by a detector circuit (30). When the presence of a signal is detected, a gate bias circuit (32) switches a gate bias for FETs in the second amplifier circuit (20, 22) to a normal operating voltage value, and when the signal is no longer detected, the gate bias is switched to a voltage value that reduces power consumption, after a mask time has elapsed. In a distortion feedback-type high-frequency amplifier circuit, a means for cutting off a circuit portion for the adjustment of each of a distortion extracting circuit and an inverse distortion adding circuit is achieved by switching FET gate voltage so as to put the corresponding amplifier in a virtually cutoff condition.Type: ApplicationFiled: August 12, 2004Publication date: January 20, 2005Inventor: Masafumi Shigaki
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Publication number: 20040189533Abstract: An antenna coupling module for electromagnetically coupling a planar antenna and a planar type oxide superconductive high frequency circuit not reducing the antenna effective area and sharply reducing the signal loss due to coupling, comprised of a planar antenna and a substrate forming a planar superconductive high frequency circuit arranged in a perpendicular direction with respect to the element surface of the planar antenna and having the planar antenna and the superconductive high frequency circuit electromagnetically coupled.Type: ApplicationFiled: March 3, 2004Publication date: September 30, 2004Applicant: FUJITSU LIMITEDInventors: Kazunori Yamanaka, Isao Nakazawa, Masafumi Shigaki
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Publication number: 20040119480Abstract: A monitoring system for high-frequency circuits which minimizes the insertion loss of additional monitoring circuits while requiring only a small space. An input coupler is placed at the input of a high-frequency circuit whose frequency response is to be monitored. The input coupler has a space where a given high-frequency probing signal can propagate, and it combines this propagating signal with a given electrical input signal. The combined signal is processed by the high-frequency circuit, and the resulting signal is supplied to an output coupler. The output coupler has a space for propagation of a high-frequency probing signal component contained in the received combined signal. The output coupler extracts this propagating signal component for the purpose of monitoring.Type: ApplicationFiled: July 24, 2003Publication date: June 24, 2004Applicant: FUJITSU LIMITEDInventors: Kazunori Yamanaka, Isao Nakazawa, Masafumi Shigaki, Manabu Kai
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Publication number: 20040041656Abstract: A dielectric waveguide which comprises a first single crystal magnesium oxide block having a surface of face (001), (100) or (010) and a first copper oxide superconducting film formed on the above-described surface in a c-axis crystal orientation perpendicular to the surface, and a method of production thereof are provided.Type: ApplicationFiled: August 26, 2003Publication date: March 4, 2004Applicant: FUJITSU LIMITEDInventors: Kazunori Yamanaka, Akihiko Akasegawa, Masafumi Shigaki, Isao Nakazawa
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Patent number: 6486734Abstract: An amplifier apparatus including a first dividing circuit disposed at the input side of an amplifier, for dividing an input signal into a primary signal to be amplified by the amplifier and an auxiliary signal for distortion detection, a distortion compensating signal generating circuit for generating a distortion compensating signal, based on the auxiliary signal and the output of the amplifier, to compensate a distortion component contained in the output of the primary amplifier and inputting the generated signal into the amplifier, and a primary signal combining circuit for combining the primary signal obtained by the first dividing circuit 1 with the distortion compensating signal. The result is that even using an auxiliary amplifier whose gain is small or without using such auxiliary amplifier in a feedback system, the distortion component contained in the output of the amplifier can be effectively compensated.Type: GrantFiled: February 23, 2001Date of Patent: November 26, 2002Assignee: Fujitsu LimitedInventors: Keiichi Oguro, Masafumi Shigaki
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Patent number: 6377118Abstract: A linearizer includes an input terminal, an output terminal, and a field-effect transistor having a gate connected to the input terminal, a drain connected to the output terminal and a source grounded. A supply voltage is supplied through a load circuit to the drain of the transistor. A gate voltage is supplied through a bias line to the gate of the transistor. The transistor is biased at a bias point at which a drain current of the transistor in response to the gate voltage is in an unsaturated region.Type: GrantFiled: August 30, 1999Date of Patent: April 23, 2002Assignee: Fujitsu LimitedInventors: Masafumi Shigaki, Takao Sasaki
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Publication number: 20010054932Abstract: An amplifier apparatus including a first dividing circuit disposed at the input side of an amplifier, for dividing an input signal into a primary signal to be amplified by the amplifier and an auxiliary signal for distortion detection, a distortion compensating signal generating circuit for generating a distortion compensating signal, based on the auxiliary signal and the output of the amplifier, to compensate a distortion component contained in the output of the primary amplifier and inputting the generated signal into the amplifier, and a primary signal combining circuit for combining the primary signal obtained by the first dividing circuit 1 with the distortion compensating signal. The result is that even using an auxiliary amplifier whose gain is small or without using such auxiliary amplifier in a feedback system, the distortion component contained in the output of the amplifier can be effectively compensated.Type: ApplicationFiled: February 23, 2001Publication date: December 27, 2001Inventors: Keiichi Oguro, Masafumi Shigaki
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Patent number: 4855895Abstract: A frequency dividing apparatus having an input signal terminal and a divided signal terminal, whereby a high frequency input to the input signal terminal is divided by a mixer having a first input terminal connected to the input signal terminal having a second input terminal, and having an output terminal connected to the divided signal terminal. A frequency divider is provided having a fixed frequency dividing ratio. The frequency divider has an input terminal connected to the divided signal terminal and an output terminal connected to the second input terminal of the mixer.Type: GrantFiled: May 19, 1988Date of Patent: August 8, 1989Assignee: Fujitsu LimitedInventors: Masafumi Shigaki, Hiroshi Kurihara, Hidetoshi Nishi
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Patent number: 4612514Abstract: A feedback amplifier circuit includes an inversion circuit, a level shift circuit, and a feedback resistive element. The inversion circuit includes an input active element and a load element connected in cascade with respect to a voltage source. The level shift circuit includes a field effect transistor having a gate connected to the output of the inversion circuit, a diode or diodes, a constant current active load connected in cascade with respect to the voltage source, and the feedback resistive element is connected between the output of the level shift circuit and the input of the inversion circuit.Type: GrantFiled: March 26, 1984Date of Patent: September 16, 1986Assignee: Fujitsu LimitedInventors: Masafumi Shigaki, Yukio Takeda