Patents by Inventor Christos Christodoulou

Christos Christodoulou 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: 20200153535
    Abstract: Systems and methods of using machine-learning in a cognitive radio to avoid a jammer are described. Smoothed power spectral density is used to detect activity in a sub-band and basic characteristics of different signals therein extracted. If unable to classify the signals as either a valid signal or a jammer using the basic characteristics, ANN-based classification with cumulants features of the signals is used. Multiple periods are used to train sensing and communications (S/C) polices to track and avoid a jammer using RL (e.g. Q learning). The ANN has input neurons of higher order cumulants of a sensing channel and a single output neuron. The S/C polices are coupled during training and communication using negative or decreasing rewards based on the time the sensing policy takes to determine jammer presence and that the cognitive radio is jammed. A feedback channel provides a new communications channel to a radio transmitting to the cognitive radio.
    Type: Application
    Filed: November 9, 2018
    Publication date: May 14, 2020
    Inventors: Sudharman Jayaweera Kankanamge, Christos Christodoulou
  • Patent number: 7589674
    Abstract: A self-similar multiband reconfigurable antenna includes a planar antenna structure formed on a surface of a substrate, the antenna structure including symmetrically opposed self-similar geometry antenna arms defining a self-similar or Sierpinski gasket configuration for each arm of the antenna. MEMS type switches are provided for operatively connecting adjacent antenna patches on each arm of the antenna configuration, and a voltage source is provided for selectively actuating the switches. Selective actuation of the switches enables up to four different antenna configurations each having a different resonant frequency, and wherein each resonant frequency demonstrates a similar radiation pattern.
    Type: Grant
    Filed: July 18, 2006
    Date of Patent: September 15, 2009
    Assignee: STC.UNM
    Inventors: Dimitrios Anagnostou, Guizhen Zheng, Ioannis Papapolymerou, Christos Christodoulou
  • Publication number: 20090207091
    Abstract: A self-similar multiband reconfigurable antenna includes a planar antenna structure formed on a surface of a substrate, the antenna structure including symmetrically opposed self-similar geometry antenna arms defining a self-similar or Sierpinski gasket configuration for each arm of the antenna. MEMS type switches are provided for operatively connecting adjacent antenna patches on each arm of the antenna configuration, and a voltage source is provided for selectively actuating the switches. Selective actuation of the switches enables up to four different antenna configurations each having a different resonant frequency, and wherein each resonant frequency demonstrates a similar radiation pattern.
    Type: Application
    Filed: July 18, 2006
    Publication date: August 20, 2009
    Inventors: Dimitrios Anagnostou, Guizhen Zheng, Ioannis Papapolymerou, Christos Christodoulou
  • Patent number: 6310346
    Abstract: A tuned antenna-coupled infrared detector is made possible by application of a bias voltage in the range of a few hundred millivolts. The use of first and second antenna arms connected to the detector makes possible polarization tuning which eliminates the need for bulk-optical polarization filters. An alternative tuned detector is one in which the antenna is frequency tuned by a capacitative device to make the detector particularly responsive to 8 um to 12 um infrared radiation. When integrated into focal plane arrays, these detectors can be used in remote-sensing systems to facilitate enhanced image recognition, feature extraction and image-clutter removal.
    Type: Grant
    Filed: June 28, 1999
    Date of Patent: October 30, 2001
    Assignee: University of Central Florida
    Inventors: Glenn D. Boreman, Iulian Cordreanu, Christophe Fumeaux, Michael Gritz, Christos Christodoulou
  • Patent number: 6037590
    Abstract: An antenna-coupled infrared detector with polarization tuning over approximately 90 degrees by application of a bias voltage in the range of a few hundred millivolts. This mechanism of polarization tuning eliminates the need for bulk-optical polarization filters. When integrated into focal plane arrays, these detectors can be used in remote-sensing systems to facilitate enhanced image recognition, feature extraction and image-clutter removal. A preferred version of the antenna has longitudinal metal antenna arms extending outward from an infrared(IR) sensor in a spiral pattern, polarization tuning devices connected between the antenna arms, and a voltage for controlling the polarization tuning devices, wherein the polarization tuning devices enable real-time control of current distribution in the arms. The infrared(IR) sensors can be tunnel diodes, schottky diodes, photovoltaics, photoconductors, and pyroelectrics.
    Type: Grant
    Filed: January 7, 1998
    Date of Patent: March 14, 2000
    Assignee: University of Central Florida
    Inventors: Glenn D. Boreman, Aristide Dogariu, Christos Christodoulou