Patents by Inventor Stefan Liedtke

Stefan Liedtke 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: 6600441
    Abstract: A radar detector for exploration of subsurface embedded objects comprising an antenna array (1) for high-frequency electromagnetic waves, which is connected and individually switchable with at least one transmit/receive unit, a time-controlled signal processor, an evaluation device for SAR and a display device. The antenna array (1) exhibiting at least three antennas (sx, rx, sy, ry) scanning an area by their positioning.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: July 29, 2003
    Assignee: Hilti Aktiengesellschaft
    Inventors: Stefan Liedtke, Harald Schmitzer, John Ewen, Klaus Dass
  • Publication number: 20020044078
    Abstract: A radar detector for exploration of subsurface embedded objects comprising an antenna array (1) for high-frequency electromagnetic waves, which is connected and individually switchable with at least one transmit/receive unit, a time-controlled signal processor, an evaluation device for SAR and a display device. The antenna array (1) exhibiting at least three antennas (sx, rx, sy, ry) scamiing an area by their positioning.
    Type: Application
    Filed: October 9, 2001
    Publication date: April 18, 2002
    Inventors: Stefan Liedtke, Harald Schmitzer, John Ewen, Klaus Dass
  • Patent number: 6366232
    Abstract: A method of detecting foreign bodies in a medium with a radar having a transceiver, and including emitting a radar wave through a wall surface into the medium with the transceiver, detecting a radar signal reflected in the medium, pre-processing the reflected radar signal and subjecting the pre-processed radar signal to evaluation and assessment, determining a characteristic of a foreign body at a stationary position of the transceiver with an algorithm which is based on a pre-processed, digitalized receivable signal, which characteristic permits to recognize differences between a shape of the reflected radar signal and stored comparison values, and conducting a comparison assessment of the shape differences of the reflected signal against predetermined threshold values.
    Type: Grant
    Filed: October 7, 1999
    Date of Patent: April 2, 2002
    Assignee: Hilti Aktiengesellschaft
    Inventors: Stefan Liedtke, Stefan Tichy
  • Patent number: 6246354
    Abstract: A method of determining a relative permittivity (&egr;r) of concrete including providing a radar apparatus to be positioned on a concrete mass and having a transmitting antenna (2) for emitting a radar wave into the concrete mass and a receiving antenna (3) for detecting a cross-signal generated by the radar wave emitted into the concrete mass by the transmitting antenna, electronically processing the cross-signal, and determining the relative permittivity (&egr;r) by determining, with an algorithm, a frequency-dependent amplitude shifting in a spectrum of a signal section with in a predetermined time slot (t1); and using the so determined permittivitiy for depth scaling and determining presence of foreign bodies.
    Type: Grant
    Filed: October 7, 1999
    Date of Patent: June 12, 2001
    Assignee: Hilti Aktiengesellschaft
    Inventors: Stefan Liedtke, Stefan Tichy
  • Patent number: 6163292
    Abstract: A method of determining the ability of a medium to absorb electromagnetic waves including placing antenna unit (10) having spaced transmitting and receiving antennas (2 and 3) on a limiting surface of a medium (13), emitting, with the transmitting antenna (2), a radar wave into the medium (13) which is detected as a cross-signal by the receiving antenna (3), pre-processing and digitalizing the cross-signal, and, thereafter, analyzing the cross-signal with an algorithm for determining the ability of the medium to absorb electromagnetic waves and, thereby, a type of the medium; and an electromagnetic sensor the operation of which is based on the method.
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: December 19, 2000
    Assignee: Hilti Aktiengesellschaft
    Inventors: Stefan Liedtke, Stefan Tichy