Patents by Inventor Tadahiko Maeda

Tadahiko Maeda 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: 5517676
    Abstract: A portable radio and telephone equipment for transmitting and receiving an electric wave. The portable radio and telephone equipment includes: an antenna for transmitting and receiving an electromagnetic wave; a housing connected to the antenna, having a notch therein; and an internal circuit, connected to the antenna by way of the housing, for generating and receiving the electromagnetic wave. The portable radio and telephone equipment includes: an antenna for transmitting and receiving an electromagnetic wave; an upper portion of a housing connected to the antenna; and a lower portion of a housing connected to the upper portion of the housing via a conductor wire, so that the housing is divided into two portions in order to vary distribution pattern of the electromagnetic wave.
    Type: Grant
    Filed: December 23, 1992
    Date of Patent: May 14, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Syuichi Sekine, Tadahiko Maeda
  • Patent number: 5422598
    Abstract: A two-stage power amplifier device for use in a digital hand-held radiophone includes a first and a second amplifier circuit. The first amplifier is an exciter-stage amplifier for receiving a high-frequency input signal corresponding to a modulation signal to generate an amplified signal at its output. The second amplifier is a final-stage amplifier connected to either the input signal or the output of the exciter amplifier. A detector circuit is connected to the exciter amplifier, for monitoring variations in a bias current to be fed to the exciter amplifier, and for generating a detection signal indicative of the current variation thus detected. A linearizer circuit is connected to the detector and the final-stage amplifier.
    Type: Grant
    Filed: December 28, 1993
    Date of Patent: June 6, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Maeda, Koji Iino, Shuichi Obayashi, Syuuichi Sekine
  • Patent number: 5300939
    Abstract: The present invention relates to an apparatus for measuring antenna radiation efficiency, wherein a random field measurement method can be adopted. In this apparatus, a to-be-measured antenna and a standard antenna are situated in a frame. In the frame, a plurality of rods, which are horizontally movable and extend vertically, are supported. A plurality of radio wave scatterers whose intervals and curvatures can be determined at random are held to the rods. In the frame, a random field is created by the radio wave scatterers.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: April 5, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Maeda, Yoshiaki Tsukumo, Satoshi Yasuda, Syuuichi Sekine, Shuichi Obayashi
  • Patent number: 4968983
    Abstract: A radiation field characteristic measuring apparatus comprises a rotating device for rotating a tested object through the total solid angle thereof, and a device for receiving electromagnetic waves radiated from the object, thereby measuring electromagnetic field characteristics of the object with respect to the total solid angle. According to the present invention, almost all the components of the rotating device are formed of a nonmetallic material, and spaces to allow the passage of the electromagnetic waves are formed in the components of the rotating device. Thus, reflection and scattering of the electromagnetic waves are suppressed, so that the radiation field characteristics of the tested object, with respect to the total solid angle thereof, can be obtained with high accuracy. Also, the effective radiated power is measured with use of the arrival probability density function of radio waves as a weighting function.
    Type: Grant
    Filed: January 19, 1989
    Date of Patent: November 6, 1990
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Tadahiko Maeda
  • Patent number: 4431738
    Abstract: In a plant tissue and cell cultivation, a method for facilitating both cell multiplication and differentiation is attained by conducting the cultivation in a culture medium containing an extract of micro algae such as Chlorella, Scenedesmus and Spirulina.
    Type: Grant
    Filed: September 21, 1981
    Date of Patent: February 14, 1984
    Assignee: Chlorella Industry Co., Ltd.
    Inventors: Tadahiko Maeda, Kuniaki Tanaka