Patents by Inventor Tadao Nagatsuma

Tadao Nagatsuma 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: 12165977
    Abstract: A terahertz module includes: a terahertz chip which includes an active device which emits a terahertz wave; and a dielectric substrate coupled to the terahertz chip. The terahertz chip includes a semiconductor substrate. The active device is disposed on an upper surface of the semiconductor substrate. A cutout is formed in a portion of a first side surface, among a plurality of side surfaces of the dielectric substrate, the cutout extending from an upper side of the first side surface to a lower side of the first side surface. The terahertz chip is fit into the cutout in such a direction that the upper surface of the semiconductor substrate is parallel to the first side surface and the semiconductor substrate is arranged in a bottom side of the cutout.
    Type: Grant
    Filed: July 8, 2021
    Date of Patent: December 10, 2024
    Assignees: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki Fujita, Daniel Jonathan Headland, Tadao Nagatsuma, Yosuke Nishida
  • Publication number: 20240260244
    Abstract: According to the present invention, a laminate has: a fiber aggregate including a plurality of nanofibers aggregated into a sheet; and a reflective substrate on which the fiber aggregate is placed and which has a reflectance of 0.1% or more. In this laminate, the fiber aggregate includes: a first orientation part formed in a part of a thickness direction of the fiber aggregate; and a second orientation part formed nearer to the reflective substrate than the first orientation part and having a lower degree of orientation than the first orientation part.
    Type: Application
    Filed: July 28, 2021
    Publication date: August 1, 2024
    Applicants: Nitto Denko Corporation, OSAKA UNIVERSITY
    Inventors: Yusuke Kamano, Shotaro Masuda, Masaya Nagai, Tadao Nagatsuma, Masayuki Fujita
  • Publication number: 20230260913
    Abstract: A terahertz module includes: a terahertz chip which includes an active device which emits a terahertz wave; and a dielectric substrate coupled to the terahertz chip. The terahertz chip includes a semiconductor substrate. The active device is disposed on an upper surface of the semiconductor substrate. A cutout is formed in a portion of a first side surface, among a plurality of side surfaces of the dielectric substrate, the cutout extending from an upper side of the first side surface to a lower side of the first side surface. The terahertz chip is fit into the cutout in such a direction that the upper surface of the semiconductor substrate is parallel to the first side surface and the semiconductor substrate is arranged in a bottom side of the cutout.
    Type: Application
    Filed: July 8, 2021
    Publication date: August 17, 2023
    Inventors: Masayuki FUJITA, Daniel Jonathan HEADLAND, Tadao NAGATSUMA, Yosuke NISHIDA
  • Publication number: 20230178898
    Abstract: An UC dielectric waveguide of the embodiments includes: a dielectric substance wiring propagating a terahertz wave; and a medium disposed around the dielectric substance wiring and having a large refractive index difference with respect to the dielectric substance wiring. A THz circuit of the embodiments includes a dielectric substance THz circuit connected between a first and second UC dielectric waveguides. The dielectric substance THz circuit includes a circuit including a linear-shaped UC dielectric waveguide, a bent-shaped UC dielectric waveguide, and a Y-coupled branch circuit. There are included a first holding unit holding the first UC dielectric waveguide and a second holding unit holding the second UC dielectric waveguide. The THz circuit of the embodiments may include a 2×2 evanescent coupler. Provided is a THz circuit having mechanical strength obtained by applying the UC dielectric waveguide having high confinement and transmission efficiencies of THz waves with a simple structure.
    Type: Application
    Filed: January 26, 2023
    Publication date: June 8, 2023
    Inventors: Masayuki FUJITA, Daniel Jonathan HEADLAND, Withawat WITHAYACHUMNANKUL, Tadao NAGATSUMA
  • Publication number: 20210271099
    Abstract: The transmission device of the present embodiment includes a waveguide unit which transmits a terahertz-wave signal, and a plurality of ports provided around the waveguide unit and each composed of a waveguide and a planar lens, the waveguide unit and the ports being integrated on a planar substrate with dielectric properties. The planar lens diffuses, in an arcuate shape, a terahertz-wave signal by a reflective index set by a staggering arrangement of first through-holes, transmits the diffused terahertz-wave signal to the waveguide unit in parallel, or focuses a terahertz-wave signal which is transmitted in parallel through the waveguide unit. A beam splitter transmits a terahertz-wave signal, which is transmitted in parallel from a first planar lens, to a second planar lens, by reflection or transmission by a refractive index set by a grid arrangement of second through-holes.
    Type: Application
    Filed: February 25, 2021
    Publication date: September 2, 2021
    Applicant: Osaka University
    Inventors: Naoya Kukutsu, Masato Kikuchi, Tadao Nagatsuma, Masayuki Fujita, Daniel Jonathan Headland, Tomoki Sagisaka, Li Yi
  • Patent number: 10761126
    Abstract: Provided is an electro-optic probe for detecting an electromagnetic wave, including: an electro-optic crystal; and an optical fiber optically coupled to the electro-optic crystal, wherein a direction of a unique axis of the electro-optic crystal and a polarization direction of light from the optical fiber that enters the electro-optic crystal are set to be in line with each other, or wherein a direction of a unique axis of the electro-optic crystal and a unique polarization direction of the optical fiber are set to be in line with each other.
    Type: Grant
    Filed: June 28, 2016
    Date of Patent: September 1, 2020
    Assignee: Osaka University
    Inventors: Shintarou Hisatake, Tadao Nagatsuma, Hirohisa Uchida
  • Patent number: 10451663
    Abstract: An electromagnetic field measurement device includes a first probe and a second probe arranged in a space to measure an electric field, a reference signal generator that generates a reference signal, a first multiplier that multiplies the reference signal by a signal obtained via the first probe, a second multiplier that multiplies a signal obtained via the second probe by the signal output from the first multiplier, and a synchronous detector that extracts a signal component that is synchronous with the reference signal from the signal output from the second multiplier.
    Type: Grant
    Filed: August 9, 2016
    Date of Patent: October 22, 2019
    Assignee: OSAKA UNIVERSITY
    Inventors: Shintarou Hisatake, Tadao Nagatsuma
  • Patent number: 10276919
    Abstract: A THz device includes: an antenna electrode capable of transmitting and receiving a THz wave to free space; first transmission lines capable of transmitting the THz wave, the first transmission lines respectively connected to the antenna electrodes; an active element of which a main electrode is connected to each of the first transmission lines; second transmission lines capable of transmitting the THz wave, the second transmission lines connected to the first active device; pad electrodes respectively connected to the second transmission lines; and a low-pass filter with respect to the THz wave, the low-pass filter connected to the pad electrodes, wherein impedance matching of between the antenna electrode and the active element is performed by an impedance conversion of the first transmission lines. The THz device is capable of the high-efficiency matching between the active element and the antenna due to the impedance conversion effect of the transmission line.
    Type: Grant
    Filed: February 27, 2017
    Date of Patent: April 30, 2019
    Assignees: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Sebastian Diebold, Masayuki Fujita, Tadao Nagatsuma, Jaeyoung Kim, Toshikazu Mukai, Kazuisao Tsuruda
  • Publication number: 20180238948
    Abstract: An electromagnetic field measurement device includes a first probe and a second probe arranged in a space to measure an electric field, a reference signal generator that generates a reference signal, a first multiplier that multiplies the reference signal by a signal obtained via the first probe, a second multiplier that multiplies a signal obtained via the second probe by the signal output from the first multiplier, and a synchronous detector that extracts a signal component that is synchronous with the reference signal from the signal output from the second multiplier.
    Type: Application
    Filed: August 9, 2016
    Publication date: August 23, 2018
    Inventors: Shintarou HISATAKE, Tadao NAGATSUMA
  • Publication number: 20180188305
    Abstract: Provided is an electro-optic probe for detecting an electromagnetic wave, including: an electro-optic crystal; and an optical fiber optically coupled to the electro-optic crystal, wherein a direction of a unique axis of the electro-optic crystal and a polarization direction of light from the optical fiber that enters the electro-optic crystal are set to be in line with each other, or wherein a direction of a unique axis of the electro-optic crystal and a unique polarization direction of the optical fiber are set to be in line with each other.
    Type: Application
    Filed: June 28, 2016
    Publication date: July 5, 2018
    Applicant: OSAKA UNIVERSITY
    Inventors: Shintarou Hisatake, Tadao Nagatsuma, Hirohisa Uchida
  • Publication number: 20170250458
    Abstract: A THz device includes: an antenna electrode capable of transmitting and receiving a THz wave to free space; first transmission lines capable of transmitting the THz wave, the first transmission lines respectively connected to the antenna electrodes; an active element of which a main electrode is connected to each of the first transmission lines; second transmission lines capable of transmitting the THz wave, the second transmission lines connected to the first active device; pad electrodes respectively connected to the second transmission lines; and a low-pass filter with respect to the THz wave, the low-pass filter connected to the pad electrodes, wherein impedance matching of between the antenna electrode and the active element is performed by an impedance conversion of the first transmission lines. The THz device is capable of the high-efficiency matching between the active element and the antenna due to the impedance conversion effect of the transmission line.
    Type: Application
    Filed: February 27, 2017
    Publication date: August 31, 2017
    Applicants: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Sebastian DIEBOLD, Masayuki FUJITA, Tadao NAGATSUMA, Jaeyoung KIM, Toshikazu MUKAI, Kazuisao TSURUDA
  • Patent number: 9632247
    Abstract: The THz-wave device comprises: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an RTD device disposed on the 2D-PC waveguide.
    Type: Grant
    Filed: March 10, 2015
    Date of Patent: April 25, 2017
    Assignees: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki Fujita, Tadao Nagatsuma, Kazuisao Tsuruda, Dai Onishi
  • Patent number: 9496622
    Abstract: The photonic-crystal (PC) slab absorber includes: a two-dimensional (2D)-PC slab composed of semiconducting materials; and a lattice point periodically arranged in the 2D-PC slab, the lattice point for forming resonant-state which can capture an electromagnetic waves incident from an outside by resonating an electromagnetic wave in a band edge of a photonic band structure of the 2D-PC slab in the plane of the 2D-PC slab. The 2D-PC slab is doped with impurities and can absorb the captured electromagnetic wave in the band edge resonant frequency of the 2D-PC slab.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: November 15, 2016
    Assignees: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki Fujita, Tadao Nagatsuma, Ryoma Kakimi, Dai Onishi, Eiji Miyai
  • Publication number: 20160178843
    Abstract: The THz-wave device comprises: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an RTD device disposed on the 2D-PC waveguide.
    Type: Application
    Filed: March 10, 2015
    Publication date: June 23, 2016
    Applicants: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki FUJITA, Tadao NAGATSUMA, Kazuisao TSURUDA, Dai ONISHI
  • Patent number: 9188742
    Abstract: The terahertz-wave connector includes: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an adiabatic mode converter disposed at the edge face of the 2D-PC slab to which the 2D-PC waveguide extended, the 2D-PC waveguide extended to the adiabatic mode converter. There is provided also the THz-wave IC to which such a terahertz-wave connector is applied.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: November 17, 2015
    Assignees: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki Fujita, Tadao Nagatsuma, Tsukasa Ishigaki, Dai Onishi, Eiji Miyai
  • Publication number: 20150241630
    Abstract: The directional coupler includes: lattice points periodically arranged in the 2D-PC slab and configured to diffract optical waves, THz waves, or millimeter waves in PBG frequencies in PBG structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a first 2D-PC waveguide formed of a line defect; a second 2D-PC waveguide which can be mode-coupled to the first waveguide; a directional coupling unit disposed between the first waveguide and the second waveguide in two rows, and having lattice points between waveguides of which the radius is smaller than that of the lattice points, wherein in order to match the first waveguide with an operational band at a side of an input port from the directional coupling unit, the width of the second waveguide is narrowed so that the whole dispersion curve of the directional coupling unit is moved to a higher-frequency side.
    Type: Application
    Filed: February 26, 2015
    Publication date: August 27, 2015
    Applicants: ROHM CO., LTD., OSAKA UNIVERSITY
    Inventors: Masayuki FUJITA, Tadao NAGATSUMA, Dai ONISHI, Eiji MIYAI
  • Publication number: 20140255040
    Abstract: The photonic-crystal (PC) slab absorber includes: a two-dimensional (2D)-PC slab composed of semiconducting materials; and a lattice point periodically arranged in the 2D-PC slab, the lattice point for forming resonant-state which can capture an electromagnetic waves incident from an outside by resonating an electromagnetic wave in a band edge of a photonic band structure of the 2D-PC slab in the plane of the 2D-PC slab. The 2D-PC slab is doped with impurities and can absorb the captured electromagnetic wave in the band edge resonant frequency of the 2D-PC slab.
    Type: Application
    Filed: March 7, 2014
    Publication date: September 11, 2014
    Applicants: OSAKA UNIVERSITY, ROHM CO., LTD.
    Inventors: Masayuki FUJITA, Tadao NAGATSUMA, Ryoma KAKIMI, Dai ONISHI, Eiji MIYAI
  • Publication number: 20140248020
    Abstract: The terahertz-wave connector includes: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an adiabatic mode converter disposed at the edge face of the 2D-PC slab to which the 2D-PC waveguide extended, the 2D-PC waveguide extended to the adiabatic mode converter. There is provided also the THz-wave IC to which such a terahertz-wave connector is applied.
    Type: Application
    Filed: March 4, 2014
    Publication date: September 4, 2014
    Applicants: OSAKA UNIVERSITY, ROHM CO., LTD.
    Inventors: Masayuki FUJITA, Tadao NAGATSUMA, Tsukasa ISHIGAKI, Dai ONISHI, Eiji MIYAI
  • Publication number: 20140132466
    Abstract: A dielectric film has a main surface and a back surface and is formed of resin. Electrodes that can receive or transmit an electromagnetic wave having a frequency of not less than 0.05 THz and not more than 10 THz in the terahertz band are formed on the main surface of the dielectric film. The electrodes constitute a tapered slot antenna. The dielectric film and the electrodes are formed of a flexible printed circuit board. A semiconductor device that is operable at a frequency in the terahertz band is mounted on the main surface of the dielectric film so as to be electrically connected to the electrodes.
    Type: Application
    Filed: November 4, 2013
    Publication date: May 15, 2014
    Applicants: OSAKA UNIVERSITY, NITTO DENKO CORPORATION
    Inventors: Masami INOUE, Masayuki HODONO, Mitsuru HONJO, Tadao NAGATSUMA, Masayuki FUJITA
  • Patent number: 7511511
    Abstract: A biological tissue equivalent phantom unit to be used by the specific absorption rate measuring system for evaluating absorption of electromagnetic wave energy includes a biological tissue equivalent phantom for absorbing an electromagnetic wave. In addition, two or more electro-optical crystals are arranged at two or more measurement points in the biological tissue equivalent phantom. The electro-optical crystals have a dielectric constant that is approximately equal to that of the biological tissue equivalent phantom. Two or more optical fibers are laid in the biological tissue equivalent phantom for optically connecting each of the electro-optical crystals to an external destination.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: March 31, 2009
    Assignees: NTT DoCoMo, Inc., Nippon Telegraph and Telephone Corporation
    Inventors: Teruo Onishi, Ryo Yamaguchi, Shinji Uebayashi, Tadao Nagatsuma, Naofumi Shimizu, Hiroyoshi Togo