Patents by Inventor L. Fredrik Liljegren

L. Fredrik Liljegren 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).

  • Active prevention of radio frequency emissions from a mobile communications unit in restricted areas
    Patent number: 6246891
    Abstract: To enable use of an intelligent mobile communication unit (1) in areas where there are restrictions on the emission of radio frequency energy, the unit is provided with means (3) for actively preventing radio frequency radiation from the unit (1) even if non-radio frequency energy emitting parts of the unit (1) are operable.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: June 12, 2001
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: B. Johanna Isberg, Mikael Dahlkvist, L. Fredrik Liljegren, Ulf C. Björkengren, Anders Khullar