Patents by Inventor Keun Kwan Ryu

Keun Kwan Ryu 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).

  • Lowpass filter for high frequency applications
    Patent number: 6590476
    Abstract: The present invention relates to a lowpass filter for effectively suppress a spurious in stop-band. The lowpass filter includes an input port microstrip element; an output port microstrip element; a first open-ended microstrip element; a second open-ended microstrip element; a first connector microstrip element; and, a second connector microstrip element. The each open-ended microstrips of the present invention is composed of distributed elements and distributed resistances connected each others in series and operated as a capacity, has a large impedance of the microstrip by low influence of a resistance in case of a low frequency, and has a small impedance of the microstrip by high influence of a resistance value in case of a high frequency. The present invention can effectively suppress the spurious characteristic, which is a disadvantage of the conventional lowpass filter composed of transmission lines at the RF band or the microwave band, by inserting resistance elements in open-ended microstrips.
    Type: Grant
    Filed: December 31, 2001
    Date of Patent: July 8, 2003
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Moon Que Lee, Keun Kwan Ryu, In Bok Yom, Seong-Pal Lee
  • Lowpass filter for high frequency applications
    Publication number: 20020109566
    Abstract: The present invention relates to a lowpass filter for effectively suppress a spurious in stop-band. The lowpass filter includes an input port microstrip element; an output port microstrip element; a first open-ended microstrip element; a second open-ended microstrip element; a first connector microstrip element; and, a second connector microstrip element. The each open-ended microstrips of the present invention is composed of distributed elements and distributed resistances connected each others in series and operated as a capacity, has a large impedance of the microstrip by low influence of a resistance in case of a low frequency, and has a small impedance of the microstrip by high influence of a resistance value in case of a high frequency. The present invention can effectively suppress the spurious characteristic, which is a disadvantage of the conventional lowpass filter composed of transmission lines at the RF band or the microwave band, by inserting resistance elements in open-ended microstrips.
    Type: Application
    Filed: December 31, 2001
    Publication date: August 15, 2002
    Inventors: Moon Que Lee, Keun Kwan Ryu, In Bok Yom, Seong-Pal Lee