Patents by Inventor Hsi-Tien Chang

Hsi-Tien Chang 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).

  • Downhole pulse radar
    Patent number: 4814768
    Abstract: A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole.
    Type: Grant
    Filed: September 28, 1987
    Date of Patent: March 21, 1989
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventor: Hsi-Tien Chang