Patents by Inventor Takao Kawahara

Takao Kawahara 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: 8988089
    Abstract: A first switch is arranged such that a first terminal thereof is connected to an AC test unit and a second terminal thereof is connected to an I/O terminal and a DC test unit. A first switch is configured so as to be capable of switching states between a connection state in which the first terminal and the second terminal are connected to each other, and a disconnection state in which they are disconnected from each other. A bypass capacitor is arranged between the first terminal and the second terminal, and is configured to bypass the frequency component which is cut off by the first switch.
    Type: Grant
    Filed: April 22, 2010
    Date of Patent: March 24, 2015
    Assignee: Advantest Corporation
    Inventors: Takao Kawahara, Takayuki Nakamura
  • Patent number: 8547124
    Abstract: A DUT is connected to an I/O terminal. An AC test unit performs an AC test operation for the DUT. A DC test unit performs a DC test operation for the DUT. An optical semiconductor switch is arranged such that a first terminal thereof is connected to the AC test unit and a second terminal thereof is connected to the I/O terminal. The optical semiconductor switch 10 is configured to be capable of switching states, according to control signals input to control terminals, between a connection state in which the first terminal and the second terminal are connected to each other, and a disconnection state in which they are disconnected from each other. A first impedance circuit is arranged on a signal line for the control signal to be input to the positive-electrode control terminal. Furthermore, a second impedance circuit is arranged on a signal line for the control signal to be input to the negative-electrode control terminal.
    Type: Grant
    Filed: April 22, 2010
    Date of Patent: October 1, 2013
    Assignee: Advantest Corporation
    Inventors: Takao Kawahara, Takayuki Nakamura
  • Patent number: 8203347
    Abstract: A reflection element determination device derives error factors in a first signal source and a second signal source based on measurement results of a signal in respective states in which reflection elements are respectively connected to the first signal source and the second signal source, and measurement results of a signal in a state in which the first signal source and the second signal source are connected with each other via a transmission element, derives transmission characteristics of the transmission element based on the measurement results of a signal in the state in which the first signal source and the second signal source are connected with each other via the transmission element and the derived error factors, and determines whether the reflection elements realize predetermined reflection states based on the derived transmission characteristics of the transmission element and transmission characteristics of the transmission element which have been known before the derivation, where the transmissi
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: June 19, 2012
    Assignee: Advantest Corporation
    Inventors: Yoshikazu Nakayama, Takao Kawahara, Masato Haruta
  • Publication number: 20120019272
    Abstract: A DUT is connected to an I/O terminal. An AC test unit performs an AC test operation for the DUT. A DC test unit performs a DC test operation for the DUT. An optical semiconductor switch is arranged such that a first terminal thereof is connected to the AC test unit and a second terminal thereof is connected to the I/O terminal. The optical semiconductor switch 10 is configured to be capable of switching states, according to control signals input to control terminals, between a connection state in which the first terminal and the second terminal are connected to each other, and a disconnection state in which they are disconnected from each other. A first impedance circuit is arranged on a signal line for the control signal to be input to the positive-electrode control terminal. Furthermore, a second impedance circuit is arranged on a signal line for the control signal to be input to the negative-electrode control terminal.
    Type: Application
    Filed: April 22, 2010
    Publication date: January 26, 2012
    Applicant: ADVANTEST CORPORATION
    Inventors: Takao Kawahara, Takayuki Nakamura
  • Publication number: 20110291682
    Abstract: A first switch is arranged such that a first terminal thereof is connected to an AC test unit and a second terminal thereof is connected to an I/O terminal and a DC test unit. A first switch is configured so as to be capable of switching states between a connection state in which the first terminal and the second terminal are connected to each other, and a disconnection state in which they are disconnected from each other. A bypass capacitor is arranged between the first terminal and the second terminal, and is configured to bypass the frequency component which is cut off by the first switch.
    Type: Application
    Filed: April 22, 2010
    Publication date: December 1, 2011
    Applicant: ADVANTEST CORPORATION
    Inventors: Takao Kawahara, Takayuki Nakamura
  • Publication number: 20100042347
    Abstract: A reflection element determination device derives error factors in a first signal source and a second signal source based on measurement results of a signal in respective states in which reflection elements are respectively connected to the first signal source and the second signal source, and measurement results of a signal in a state in which the first signal source and the second signal source are connected with each other via a transmission element, derives transmission characteristics of the transmission element based on the measurement results of a signal in the state in which the first signal source and the second signal source are connected with each other via the transmission element and the derived error factors, and determines whether the reflection elements realize predetermined reflection states based on the derived transmission characteristics of the transmission element and transmission characteristics of the transmission element which have been known before the derivation, where the transmissi
    Type: Application
    Filed: August 24, 2007
    Publication date: February 18, 2010
    Applicant: ADVANTEST CORPORATION
    Inventors: Yoshikazu Nakayama, Takao Kawahara, Masato Haruta
  • Patent number: 7075488
    Abstract: An insulative member is formed with a hole. An antenna element is provided as a conductive foil adhered onto the insulative member and having a contact section opposing to the hole. A conductive member is fitted into the hole through the contact section of the antenna element, such that a part of the contact section is clamped between an outer face of the conductive member and an inner face of the hole.
    Type: Grant
    Filed: September 28, 2004
    Date of Patent: July 11, 2006
    Assignee: Yokowo Co., Ltd.
    Inventors: Takao Kawahara, Seiji Go, Yasuhiro Minoura
  • Publication number: 20050068235
    Abstract: An insulative member is formed with a hole. An antenna element is provided as a conductive foil adhered onto the insulative member and having a contact section opposing to the hole. A conductive member is fitted into the hole through the contact section of the antenna element, such that a part of the contact section is clamped between an outer face of the conductive member and an inner face of the hole.
    Type: Application
    Filed: September 28, 2004
    Publication date: March 31, 2005
    Inventors: Takao Kawahara, Seiji Go, Yasuhiro Minoura
  • Patent number: 6522300
    Abstract: A whip antenna is movable between a first position corresponding to a state in which the whip antenna is extended from a casing of the mobile communication terminal, and a second position corresponding to a state the whip antenna is accommodated within the casing. A built-in antenna is disposed within the casing. A power feeding circuit is disposed within the casing. A first matching circuit has a first impedance, through which the power feeding circuit and the whip antenna are electrically connected when the whip antenna is placed at the first position. A second matching circuit has a second impedance which is higher than the first impedance, through which the whip antenna is grounded when the whip antenna is placed at the second position. A switch mechanism is opened so that the built-in antenna is electrically disconnected from the power feeding circuit when the whip antenna is placed at the first position, and closed so that the built-in antenna is electrically connected to the power feeding circuit.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: February 18, 2003
    Assignee: Yokowo Co., Ltd.
    Inventors: Tadashi Oshiyama, Atsushi Sato, Katsutoshi Okubo, Takao Kawahara, Seiji Gou
  • Publication number: 20020126050
    Abstract: A whip antenna is movable between a first position corresponding to a state in which the whip antenna is extended from a casing of the mobile communication terminal, and a second position corresponding to a state the whip antenna is accommodated within the casing. A built-in antenna is disposed within the casing. A power feeding circuit is disposed within the casing. A first matching circuit has a first impedance, through which the power feeding circuit and the whip antenna are electrically connected when the whip antenna is placed at the first position. A second matching circuit has a second impedance which is higher than the first impedance, through which the whip antenna is grounded when the whip antenna is placed at the second position. A switch mechanism is opened so that the built-in antenna is electrically disconnected from the power feeding circuit when the whip antenna is placed at the first position, and closed so that the built-in antenna is electrically connected to the power feeding circuit.
    Type: Application
    Filed: December 28, 2001
    Publication date: September 12, 2002
    Applicant: Yokowo Co., Ltd.
    Inventors: Tadashi Oshiyama, Atsushi Sato, Katsutoshi Okubo, Takao Kawahara, Seiji Gou
  • Patent number: 6271804
    Abstract: An antenna for mounting on a vehicle which restrains damping of a signal voltage by reducing a stray capacitance of a signal path and has an improved antenna characteristic and a short physical length, and an antenna element which is suitable for an antenna for mounting on a vehicle and is flexible by using a helical coil of a large winding diameter are provided. In the antenna for mounting on a vehicle, with respect to a band signal having a short wavelength of a plurality of band signals to be transmitted/received, an antenna element is caused to resonate with a physical length shorter than ¼ of the wavelength of the band signal. A linear line portion is provided at the proximal end, and the antenna element is provided at a predetermined distance from vehicle body and a conductive member of the same electric potential as the vehicle body. The stray capacitance between the proximal end portion of the antenna element and the vehicle body is small, and a signal voltage is outputted without being damped.
    Type: Grant
    Filed: December 30, 1999
    Date of Patent: August 7, 2001
    Assignee: Yokowo Co., Ltd.
    Inventors: Wasuke Yanagisawa, Ryo Horie, Shozaburo Kameda, Takao Kawahara, Tomio Anbe, Katsuo Miki
  • Patent number: 6259411
    Abstract: The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
    Type: Grant
    Filed: July 20, 1999
    Date of Patent: July 10, 2001
    Assignee: Yokowo Co., Ltd.
    Inventors: Wasuke Yanagisawa, Ryo Horie, Shozaburo Kameda, Takao Kawahara, Tomio Anbe, Katsuo Miki
  • Patent number: 6256000
    Abstract: A motor-driven antenna device in which an antenna element (10) has a short protruding length so that the outer dimension of the entire device is reduced, and in which damping of an AM-band signal by a signal path is restrained with a small stray capacitance. A rack cord (12) to be meshed with a pinion gear (24) is connected to a proximal portion of the antenna element (10) made of a helical coil over its entire length, and the antenna element (10) is caused to protrude and move to be housed by rotational driving of a motor drive section. The rack cord (12), the motor drive section and the pinion gear (24) are housed in a case (14), and a guide (26) to which the rack cord (12) is abutted and moves while bending is provided in the case (14). Thus, the rack cord (12) is abutted and moves to the guide (26) by the movement of the antenna element (10).
    Type: Grant
    Filed: July 20, 1999
    Date of Patent: July 3, 2001
    Assignee: Yokowo Co., Ltd.
    Inventors: Wasuke Yanagisawa, Ryo Horie, Takumi Yano, Takao Kawahara, Yuichi Kagoshima, Tomio Anbe
  • Patent number: 5995064
    Abstract: The antenna element (1) of a long conductor is formed with at least one returned portion (1a) arranged substantially in parallel to a longitudinal direction of the antenna element. In practice, a physical length of the antenna element in the longitudinal direction is determined to such a length as to be substantially resonated in a first frequency band, and the at least one returned portion (1a) is formed in such a way as to be resonated in a second frequency band twice higher than the first frequency band on the basis of an electric coupling with the adjacent antenna element.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: November 30, 1999
    Assignee: Kabushiki Kaisha Yokowa, also trading as Yokowo Co., Ltd.
    Inventors: Wasuke Yanagisawa, Ryo Horie, Takao Kawahara, Tadashi Oshiyama, Michio Arai, Takumi Yano, Atsushi Sato
  • Patent number: 5453755
    Abstract: A plurality of insulators are disposed in holes, respectively, defined in a metal plate of a waveguide of a circularly-polarized-wave flat antenna. Each insulator has a through-hole and a protrusion. The through-hole extends from the outside of the metal plate to the inside of the waveguide. The protrusion protrudes outward beyond the metal plate. The protrusion has a groove which is open to the outside. Curl antenna elements each have a shaft portion, an arm portion, and a curl portion. The shaft portion is fitted in the through-hole of the insulator and partly protrudes outward from the metal plate. The arm portion extends from the protruded end of the shaft portion. The curl portion is in a substantially helical shape and connected to the top of the arm portion.
    Type: Grant
    Filed: January 21, 1993
    Date of Patent: September 26, 1995
    Assignee: Kabushiki Kaisha Yokowo
    Inventors: Hisamatsu Nakano, Motoshige Sekine, Kazuhiro Yokoyama, Yukio Nakagawa, Eiichi Tanaka, Shigeru Yoshida, Masaaki Kasama, Itsuo Nakayama, Takao Kawahara