Patents by Inventor Hyung Do Choi

Hyung Do Choi 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).

  • Publication number: 20090284404
    Abstract: An electromagnetic wave absorber includes a ground layer made of a metal conductor, a dielectric layer formed on the ground layer, and a unit cell pattern made of a resistive material, and formed on the dielectric layer. The unit cell pattern includes a fundamental patch having a regular square shape, in which a rectangular recess is formed on the center of each of the respective sides, the fundamental patch being located at the center of each of the unit cell pattern, and half cross dipole patches, which are respectively disposed at the four sides of the fundamental patch at a regular angle so as to be engaged with the recesses formed on the respective sides of the fundamental patch at a regular interval.
    Type: Application
    Filed: September 10, 2008
    Publication date: November 19, 2009
    Applicant: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Dong-Uk Sim, Jong Hwa Kwon, Sang Il Kwak, Hyung Do Choi
  • Publication number: 20090237323
    Abstract: An apparatus for reducing electromagnetic waves, includes an electromagnetic bandgap for reducing a surface current induced by electromagnetic waves that are emitted from a radiator; and an absorber for reducing a surface current around the electromagnetic bandgap and for diminishing diffracted waves radiated from an end of a terminal.
    Type: Application
    Filed: January 12, 2009
    Publication date: September 24, 2009
    Inventors: Sang il Kwak, Jong Hwa Kwon, Dong-Uk Sim, Hyung-Do Choi, Chang-Joo Kim
  • Patent number: 7589692
    Abstract: A planar inverted F antenna having a radiation patch having an asymmetric shape of linearly-tapered rectangle with a plurality of corrugated hollows is disclosed. The planar inverted F antenna having a radiation patch, includes: a first radiation patch for radiating a signal; a ground plate for grounding the first radiation patch; a feeding line for supplying an electric power to the first radiation patch; a short plate having one side coupled to the first radiation patch and other side coupled to the ground plate for shorting the first radiation patch, wherein the first radiation patch having an asymmetrical shape of linearly tapered rectangle and has one or more corrugated hollows.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: September 15, 2009
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Byung-Chan Kim, Je-Hoon Yun, Hyung-Do Choi
  • Patent number: 7588700
    Abstract: Disclosed is an electromagnetic shielding material with enhanced shielding effectiveness and mechanical property by employing a carbon nanotube and a metal as an electrical conductor. The electromagnetic shielding material includes a polymer resin for a matrix and two conductive fillers having a carbon nanotube and a metal, wherein a volume percent of the carbon nanotube ranges about 0.2% to about 10% and a volume percent of the metal powder ranges about 7.0% to about 30% so that the total volume percent of the conductive filler is in a range of about 7.2% to about 40%.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: September 15, 2009
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Jong-Hwa Kwon, Hyung-Do Choi, Ho-Gyu Yoon, Yoon-Jin Kim
  • Publication number: 20090201212
    Abstract: An antenna system includes an antenna transmitting and receiving a signal; a power feeding line feeding electric power to the antenna; and a metal conductor ground electrically connected to the power feeding line. Further, the metal conductor ground includes an electromagnetic bandgap.
    Type: Application
    Filed: December 17, 2008
    Publication date: August 13, 2009
    Applicant: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Dong-Uk Sim, Jong Hwa Kwon, Sang II Kwak, Hyung Do Choi
  • Publication number: 20090147428
    Abstract: A metal case for preventing electrostatic discharge includes an electromagnetic bandgap restricting current generated by electrostatic discharge and formed by arrangement of unit cells. Further, a method of forming a metal case preventing an electrostatic discharge includes forming an electromagnetic bandgap by arranging a plurality of unit cells; and forming a metal case having the electromagnetic bandgap to restrict current generated by the electrostatic discharge.
    Type: Application
    Filed: December 10, 2008
    Publication date: June 11, 2009
    Applicant: Electronics and Telecommunications Research Institute
    Inventors: Jong Hwa KWON, Dong-Uk SIM, Sang Il KWAK, Hyung Do CHOI
  • Publication number: 20090027279
    Abstract: A method of reducing electromagnetic field using metamaterial and a portable or wearable terminal having a structure for reducing an electromagnetic field using a metamaterial are provided. The method includes deciding a body contacting part of the portable or wearable terminal; and disposing an electromagnetic field reducing unit formed of metamaterial between an antenna and the decided body contacting part, wherein the metamaterial including a conductor and a dielectric adjusts a permittivity.
    Type: Application
    Filed: September 18, 2008
    Publication date: January 29, 2009
    Inventors: Hyung-Do Choi, Dong-Ho Kim, Dong-Uk Sim, Jae-Ick Choi, Ae-Kyoung Lee
  • Publication number: 20080079638
    Abstract: A method of reducing electromagnetic field using metamaterial and a terminal having a structure for reducing an electromagnetic field using a metamaterial are provided. The method includes the steps of: deciding a body contacting part of a portable terminal or a wearable terminal; and disposing an electromagnetic field absorption member formed of metamaterial between an antenna and the decided body contacting part.
    Type: Application
    Filed: December 27, 2006
    Publication date: April 3, 2008
    Inventors: Hyung-Do Choi, Dong-Ho Kim, Dong-Uk Sim, Jae-Ick Choi, Ae-Kyoung Lee
  • Patent number: 7336230
    Abstract: A method for measuring electromagnetic radiation pattern and gain of radiator using TEM waveguide is disclosed. The method includes the steps of: a) measuring powers of output port of a transverse electric and magnetic (TEM) waveguide by changing arrangements of the radiator located within the TEM waveguide; and b) estimating a radiation power density of the radiator in free space, wherein the radiator is modeled as a dipole moment based on the powers of the output port of the TEM waveguide.
    Type: Grant
    Filed: June 22, 2004
    Date of Patent: February 26, 2008
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Ae-Kyoung Lee, Hyung-Do Choi, Jeong-Ki Pack
  • Publication number: 20070132640
    Abstract: A planar inverted F antenna having a radiation patch having an asymmetric shape of linearly-tapered rectangle with a plurality of corrugated hollows is disclosed. The planar inverted F antenna having a radiation patch, includes: a first radiation patch for radiating a signal; a ground plate for grounding the first radiation patch; a feeding line for supplying an electric power to the first radiation patch; a short plate having one side coupled to the first radiation patch and other side coupled to the ground plate for shorting the first radiation patch, wherein the first radiation patch having an asymmetrical shape of linearly tapered rectangle and has one or more corrugated hollows.
    Type: Application
    Filed: October 15, 2004
    Publication date: June 14, 2007
    Applicant: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTIT
    Inventors: Byung-Chan Kim, Je-Hoon Yun, Hyung-Do Choi
  • Publication number: 20070126427
    Abstract: A method for measuring electromagnetic radiation pattern and gain of radiator using TEM waveguide is disclosed. The method includes the steps of: a) measuring powers of output port of a transverse electric and magnetic (TEM) waveguide by changing arrangements of the radiator located within the TEM waveguide; and b) estimating a radiation power density of the radiator in free space, wherein the radiator is modeled as a dipole moment based on the powers of the output port of the TEM waveguide.
    Type: Application
    Filed: June 22, 2004
    Publication date: June 7, 2007
    Inventors: Ae-Kyoung Lee, Hyung-Do Choi, Jeong-Ki Pack
  • Publication number: 20070018142
    Abstract: Disclosed is an electromagnetic shielding material with enhanced shielding effectiveness and mechanical property by employing a carbon nanotube and a metal as an electrical conductor. The electromagnetic shielding material includes a polymer resin for a matrix and two conductive fillers having a carbon nanotube and a metal, wherein a volume percent of the carbon nanotube ranges about 0.2% to about 10% and a volume percent of the metal powder ranges about 7.0% to about 30% so that the total volume percent of the conductive filler is in a range of about 7.2% to about 40%.
    Type: Application
    Filed: October 15, 2004
    Publication date: January 25, 2007
    Inventors: Jong-Hwa Kwon, Hyung-Do Choi, Ho-Gyu Yoon, Yoon-Jin Kim
  • Patent number: 6181136
    Abstract: The present invention relates to a method of manufacturing a human tissue phantom for evaluation of electromagnetic wave environment. The present invention suggests the human tissue phantom having reproductibility, being different from liquid type, after elapse of a certain period and preventing the air-gap occurring after insertion of probe, by using a composite material which is composed of a shape memory polymer as a base material and a dielectric material and a conductive material as the fillers, and also suggests the method of manufacturing the whole human body phantom.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: January 30, 2001
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Hyung Do Choi, Kwang Yun Cho, Jong Suk Chae, Ho Gyu Yoon