Patents by Inventor Keizo Cho
Keizo Cho 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: 10665954Abstract: The present invention realizes a thin dual-polarized leaky-wave antenna which uses a CRLH (Composite Right/Left Handed) transmission line and capable of obtaining a high tilt angle in a directivity in the vertical plane while suppressing cross polarization and side lobe at a target operation frequency. Specifically, the present invention provides a leaky-wave antenna including a dielectric substrate, a ground surface formed on a bottom surface of the dielectric substrate, a ground unit formed on a top surface of the dielectric substrate, and a CRLH (Composite Right/Left Handed) transmission line which is arranged adjacent to the ground unit and formed on a top surface of the dielectric substrate and uses a coplanar transmission line with a ground, in which a series capacitor (CL) and a parallel inductor (LL) constituting the CRLH transmission line are formed on a top surface of the dielectric substrate.Type: GrantFiled: May 14, 2018Date of Patent: May 26, 2020Assignee: Denki Kogyo Company, LimitedInventors: Takayoshi Sasaki, Keisuke Sato, Ichiro Oshima, Naobumi Michishita, Keizo Cho
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Publication number: 20190273324Abstract: The present invention realizes a thin dual-polarized leaky-wave antenna which uses a CRLH (Composite Right/Left Handed) transmission line and capable of obtaining a high tilt angle in a directivity in the vertical plane while suppressing cross polarization and side lobe at a target operation frequency. Specifically, the present invention provides a leaky-wave antenna including a dielectric substrate, a ground surface formed on a bottom surface of the dielectric substrate, a ground unit formed on a top surface of the dielectric substrate, and a CRLH (Composite Right/Left Handed) transmission line which is arranged adjacent to the ground unit and formed on a top surface of the dielectric substrate and uses a coplanar transmission line with a ground, in which a series capacitor (CL) and a parallel inductor (LL) constituting the CRLH transmission line are formed on a top surface of the dielectric substrate.Type: ApplicationFiled: May 14, 2018Publication date: September 5, 2019Applicant: Denki Kogyo Company, LimitedInventors: Takayoshi Sasaki, Keisuke Sato, Ichiro Oshima, Naobumi Michishita, Keizo Cho
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Publication number: 20150155630Abstract: A vertically polarized antenna having a wide relative bandwidth while having a thin structure against vertically polarized waves. The vertically polarized antenna includes: a ground plate, a conductor plate, two or more feeding conductors, and short-circuit conductors grouped with the feeding conductors, respectively. The conductor plate is arranged parallel to the ground plate such that the whole of the conductor plate is overlapped with the ground plate when seen from a direction of a normal line of the ground plate; each of the feeding conductors connects the ground plate and the conductor plate at a position different from a center of the conductor plate; and each of the short-circuit conductors connects the ground plate and the conductor plate near the feeding conductor grouped with the short-circuit conductor.Type: ApplicationFiled: July 3, 2013Publication date: June 4, 2015Applicant: Nihon Dengyo Kosaku Co., Ltd.Inventors: Huiling Jiang, Keizo Cho, Zhanghuan Li
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Patent number: 8781407Abstract: An antenna equipment includes an array antenna including a plurality of antenna elements configured to be grouped into at least one group according to each of N communication types, where N is an integer greater than or equal to 2, a selecting part selecting one of the N communication types, a transmitting part modulating outgoing data to generate an outgoing signal for antenna element or antenna elements belonging to each group for the selected communication type, and a receiving part demodulating an incoming signal from antenna element or antenna elements belonging to each group for the selected communication type to generate incoming data.Type: GrantFiled: August 11, 2011Date of Patent: July 15, 2014Assignee: NTT DoCoMo, Inc.Inventors: Yuki Inoue, Keizo Cho
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Patent number: 8688130Abstract: A disclosed base station includes a communication unit configured to receive from a mobile station a first report signal including base station specification information specifying a base station, reception quality information indicating reception quality of a signal received from the specified base station, and change request information requesting to change communication quality between the mobile station and the specified base station; and an automatic area control unit configured to determine whether the base station is specified by the base station specification information, to obtain location information indicating the location of the mobile station if the base station is specified by the base station specification information, and to change at least one base station parameter based on the reception quality information and the location information to change the reception quality at the location of the mobile station.Type: GrantFiled: September 14, 2012Date of Patent: April 1, 2014Assignee: NTT DoCoMo, Inc.Inventors: Yuki Inoue, Keizo Cho, Shinichi Mori, Hiroyuki Hosono, Akira Ishii, Kei Igarashi
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Patent number: 8588835Abstract: A disclosed base station apparatus for a mobile communication system includes a collection unit collecting measured data from one or more user equipment terminals with respect to each direction of arrival, the measured data including at least quality information of a downlink signal, a conversion unit converting the measured data into an evaluation value in accordance with a predetermined evaluation function, a deriving unit deriving a weight update amount determining directivity based on an angular distribution of the plural evaluation values, and a transmission unit transmitting a downlink signal weighted based on the weight update amount.Type: GrantFiled: July 2, 2008Date of Patent: November 19, 2013Assignee: NTT DoCoMo, Inc.Inventors: Yuki Inoue, Keizo Cho
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Publication number: 20130012225Abstract: A disclosed base station includes a communication unit configured to receive from a mobile station a first report signal including base station specification information specifying a base station, reception quality information indicating reception quality of a signal received from the specified base station, and change request information requesting to change communication quality between the mobile station and the specified base station; and an automatic area control unit configured to determine whether the base station is specified by the base station specification information, to obtain location information indicating the location of the mobile station if the base station is specified by the base station specification information, and to change at least one base station parameter based on the reception quality information and the location information to change the reception quality at the location of the mobile station.Type: ApplicationFiled: September 14, 2012Publication date: January 10, 2013Applicant: NTT DOCOMO, INC.Inventors: Yuki Inoue, Keizo Cho, Shinichi Mori, Hiroyuki Hosono, Akira Ishii, Kei Igarashi
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Patent number: 8301152Abstract: A disclosed base station includes a communication unit configured to receive from a mobile station a first report signal including base station specification information specifying a base station, reception quality information indicating reception quality of a signal received from the specified base station, and change request information requesting to change communication quality between the mobile station and the specified base station; and an automatic area control unit configured to determine whether the base station is specified by the base station specification information, to obtain location information indicating the location of the mobile station if the base station is specified by the base station specification information, and to change at least one base station parameter based on the reception quality information and the location information to change the reception quality at the location of the mobile station.Type: GrantFiled: April 25, 2008Date of Patent: October 30, 2012Assignee: NTT DoCoMo, Inc.Inventors: Yuki Inoue, Keizo Cho, Shinichi Mori, Hiroyuki Hosono, Akira Ishii, Kei Igarashi
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Publication number: 20120046001Abstract: An antenna equipment includes an array antenna including a plurality of antenna elements configured to be grouped into at least one group according to each of N communication types, where N is an integer greater than or equal to 2, a selecting part selecting one of the N communication types, a transmitting part modulating outgoing data to generate an outgoing signal for antenna element or antenna elements belonging to each group for the selected communication type, and a receiving part demodulating an incoming signal from antenna element or antenna elements belonging to each group for the selected communication type to generate incoming data.Type: ApplicationFiled: August 11, 2011Publication date: February 23, 2012Applicant: NTT DOCOMO, INC.Inventors: Yuki INOUE, Keizo Cho
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Patent number: 8078113Abstract: An adaptive antenna control method is used for a radio communication system built by a plurality of radio base stations and a plurality of terminal stations capable of communicating with the radio base stations. Each radio base station includes an adaptive antenna having a plurality of antenna elements, a distributor for generating signals to be input to the plurality of antenna elements by branching a signal of one system to be transmitted, and weighting circuits for respectively weighting transmission signals to the plurality of antenna elements. For reception by each terminal station, an interference wave power given by the transmission signal from each of the plurality of radio base stations is estimated. A weight in the adaptive antenna of each radio base station is determined to minimize a sum of square errors between reception signals and desired signals for all the radio base stations which simultaneously use the same communication channel.Type: GrantFiled: October 17, 2007Date of Patent: December 13, 2011Assignee: Nippon Telegraph and Telephone CorporationInventors: Yasushi Takatori, Keizo Cho, Toshikazu Hori, Kentaro Nishimori
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Patent number: 7873582Abstract: An antenna optimum design method according to this invention includes the steps of generating blocks by dividing a metal patch on an antenna element plane vertically and horizontally; setting reference point blocks in alternate blocks and assigning chromosomes to the reference point blocks; determining ways to arrange metal patches in blocks contiguous on one side to the reference point blocks, based on the chromosomes assigned to the reference point blocks; and searching for an optimum chromosomes to be assigned to the reference point blocks by a genetic algorithm to optimize antenna characteristics.Type: GrantFiled: January 14, 2005Date of Patent: January 18, 2011Assignee: NTT DoCoMo, Inc.Inventors: Tamami Maruyama, Fumio Kira, Keizo Cho
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Publication number: 20100311456Abstract: A disclosed base station apparatus for a mobile communication system includes a collection unit collecting measured data from one or more user equipment terminals with respect to each direction of arrival, the measured data including at least quality information of a downlink signal, a conversion unit converting the measured data into an evaluation value in accordance with a predetermined evaluation function, a deriving unit deriving a weight update amount determining directivity based on an angular distribution of the plural evaluation values, and a transmission unit transmitting a downlink signal weighted based on the weight update amount.Type: ApplicationFiled: July 2, 2008Publication date: December 9, 2010Applicant: NTT DOCOMO, INC.Inventors: Yuki Inoue, Keizo Cho
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Publication number: 20100136985Abstract: A disclosed base station includes a communication unit configured to receive from a mobile station a first report signal including base station specification information specifying a base station, reception quality information indicating reception quality of a signal received from the specified base station, and change request information requesting to change communication quality between the mobile station and the specified base station; and an automatic area control unit configured to determine whether the base station is specified by the base station specification information, to obtain location information indicating the location of the mobile station if the base station is specified by the base station specification information, and to change at least one base station parameter based on the reception quality information and the location information to change the reception quality at the location of the mobile station.Type: ApplicationFiled: April 25, 2008Publication date: June 3, 2010Applicant: NTT DoCoMo, Inc.Inventors: Yuki Inoue, Keizo Cho, Shinichi Mori, Hiroyuki Hosono, Akira Ishii, Kei Igarashi
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Publication number: 20100128620Abstract: A mobile communications system is disclosed. The mobile communications system includes a unit which causes a mobile station apparatus residing within a communication area of an arbitrary base station apparatus to measure a propagation state of a wireless signal from a surrounding base station apparatus and which collects the measurement results; and a unit which obtains location information of the mobile station apparatus.Type: ApplicationFiled: April 25, 2008Publication date: May 27, 2010Applicant: NTT DOCOMO, INC.Inventors: Yuki Inoue, Keizo Cho, Shinichi Mori, Hiroyuki Hosono, Akira Ishii, Kei Igarashi
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Publication number: 20080280634Abstract: An adaptive antenna control method is used for a radio communication system built by a plurality of radio base stations and a plurality of terminal stations capable of communicating with the radio base stations. Each radio base station includes an adaptive antenna having a plurality of antenna elements, a distributor for generating signals to be input to the plurality of antenna elements by branching a signal of one system to be transmitted, and weighting circuits for respectively weighting transmission signals to the plurality of antenna elements. For reception by each terminal station, an interference wave power given by the transmission signal from each of the plurality of radio base stations is estimated. A weight in the adaptive antenna of each radio base station is determined to minimize a sum of square errors between reception signals and desired signals for all the radio base stations which simultaneously use the same communication channel.Type: ApplicationFiled: October 17, 2007Publication date: November 13, 2008Inventors: Yasushi Takatori, Keizo Cho, Toshikazu Hori, Kentaro Nishimori
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Publication number: 20080055159Abstract: An antenna optimum design method according to this invention includes the steps of generating blocks by dividing a metal patch on an antenna element plane vertically and horizontally; setting reference point blocks in alternate blocks and assigning chromosomes to the reference point blocks; determining ways to arrange metal patches in blocks contiguous on one side to the reference point blocks, based on the chromosomes assigned to the reference point blocks; and searching for an optimum chromosomes to be assigned to the reference point blocks by a genetic algorithm to optimize antenna characteristics.Type: ApplicationFiled: January 14, 2005Publication date: March 6, 2008Applicant: NTT DoCoMo, Inc.Inventors: Tamami Maruyama, Fumio Kira, Keizo Cho
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Patent number: 7302232Abstract: An adaptive antenna control method is used for a radio communication system built by a plurality of radio base stations and a plurality of terminal stations capable of communicating with the radio base stations. Each radio base station includes an adaptive antenna having a plurality of antenna elements, a distributor for generating signals to be input to the plurality of antenna elements by branching a signal of one system to be transmitted, and weighting circuits for respectively weighting transmission signals to the plurality of antenna elements. For reception by each terminal station, an interference wave power given by the transmission signal from each of the plurality of radio base stations is estimated. A weight in the adaptive antenna of each radio base station is determined to minimize a sum of square errors between reception signals and desired signals for all the radio base stations which simultaneously use the same communication channel.Type: GrantFiled: August 28, 2001Date of Patent: November 27, 2007Assignee: Nippon Telegraph and Telephone CorporationInventors: Yasushi Takatori, Keizo Cho, Toshikazu Hori, Kentaro Nishimori
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Patent number: 6735182Abstract: In an array antenna used in a transceiver in a time division communication system such as TDD (Time Division Duplex) system, amplitude and phase of each antenna element are calibrated in a transceiver itself during actual communication without using external information. A first transmitter (1-3-1) has means (1-5-1) to send a transmit signal to an antenna element (1-1-1) as well as to at least one of the receivers (1-4-1 through 1-4-N). Other transmitter (1-3-2 through 1-3-k) except the first transmitter has means (1-5-k) which sends a transmit signal to a related antenna element (1-1-2 through 1-1-k) as well as to a first receiver (1-4-1) which relates to the first transmitter. Amplitude/phase value obtained in the first receiver (1-4-1) and amplitude/phase values obtained in other receivers (1-4-2 through 1-4-k) except the first receiver provide weighted amplitude/phase values of each antenna elements according to desired desired radiation pattern.Type: GrantFiled: June 19, 2000Date of Patent: May 11, 2004Assignee: Nippon Telegraph and Telephone CorporationInventors: Kentaro Nishimori, Keizo Cho, Yasushi Takatori, Toshikazu Hori
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Patent number: 6690952Abstract: An adaptive array antenna transceiver apparatus provides: a local signal generator 24 that outputs a signal having a frequency that corresponds to the difference between the reception frequency and the transmitting frequency; a coupler 15 that separates and extracts a part of the signals from the output of the transmitters 13; a switch 21 that selects the signal output from any one of the transmitters 13; a frequency converter 22 that converts the frequency of the signal selected by the switch 21; and a switch 23 that inputs signals output by the frequency converter 22 and selectively outputs them to any one of the plurality of paths.Type: GrantFiled: December 14, 2000Date of Patent: February 10, 2004Assignee: Nippon Telegraph & Telephone CorporationInventors: Kentaro Nishimori, Keizo Cho, Yasushi Takatori, Toshikazu Hori
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Publication number: 20020111191Abstract: An adaptive antenna control method is used for a radio communication system built by a plurality of radio base stations and a plurality of terminal stations capable of communicating with the radio base stations. Each radio base station includes an adaptive antenna having a plurality of antenna elements, a distributor for generating signals to be input to the plurality of antenna elements by branching a signal of one system to be transmitted, and weighting circuits for respectively weighting transmission signals to the plurality of antenna elements. For reception by each terminal station, an interference wave power given by the transmission signal from each of the plurality of radio base stations is estimated. A weight in the adaptive antenna of each radio base station is determined to minimize a sum of square errors between reception signals and desired signals for all the radio base stations which simultaneously use the same communication channel.Type: ApplicationFiled: August 28, 2001Publication date: August 15, 2002Applicant: Nippon Telegraph and Telephone CorporationInventors: Yasushi Takatori, Keizo Cho, Toshikazu Hori, Kentaro Nishimori