Patents by Inventor David H. Evans

David H. Evans 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: 4821041
    Abstract: A microwave patch antenna, comprising a substrate of high dielectric constant, an aperture in the substrate, a patch conductor positioned on one side of the conductor and juxtaposed over said aperture, a ground plane on the other side of the substrate and having an aperture juxtaposed to at least a substantial proportion of the patch conductor. A conductive cavity is RF-coupled to the ground plane at the aperture, the cavity extending away from the substrate and being short-circuited at its end remote therefrom; in the operating frequency range of the antenna, the cavity forms a waveguide constituting an inductance. The length of the cavity may be adjustable to tune the antenna, the length of the cavity being sufficient for the resonant frequency of the antenna to decrease with increasing cavity length.
    Type: Grant
    Filed: December 17, 1987
    Date of Patent: April 11, 1989
    Assignee: U.S. Philips Corporation
    Inventor: David H. Evans
  • Patent number: 4302612
    Abstract: This invention is concerned with the synthesis of perfluorodialdehydes from the corresponding perfluorodiesters and with intermediates useful in the preparation of the perfluorodialdehydes.
    Type: Grant
    Filed: January 26, 1978
    Date of Patent: November 24, 1981
    Assignee: Polaroid Corporation
    Inventors: David H. Evans, Richard B. Greenwald
  • Patent number: 4113738
    Abstract: This application is directed to a novel cleavage reaction whereby N-tosylsulfoximides of the following formula are converted to the corresponding sulfoximines. The relevant sulfoximides are represented by the formula: ##STR1## wherein R.sup.1 and R.sup.2 when taken individually (1) each represent an alkyl moiety containing up to 20 carbon atoms, unsubstituted with an alkali-stable group or (2) R.sup.1 is an alkyl moiety containing up to 20 carbon atoms and R.sup.2 is --(CH.sub.2).sub.n --S--R.sup.3 wherein n is greater than or equal to 2 and R.sup.3 is an alkyl moiety containing up to 20 carbon atoms and R.sup.1 and R.sup.2 when taken together represents (a) an alkylene moiety having 5 or 6 carbon atoms unsubstituted or substituted with an alkali-stable group; (b) --CH.sub.2 --.sub.x SO.sub.2 --CH.sub.2 -- wherein x is 3 or 4; or (c) --CHR--SO.sub.2 --CH.sub.2 CR'R"CH.sub.
    Type: Grant
    Filed: April 5, 1977
    Date of Patent: September 12, 1978
    Assignee: Polaroid Corporation
    Inventors: David H. Evans, Richard B. Greenwald
  • Patent number: 4107176
    Abstract: This application is directed to cycloalkanes containing the moiety --SO.sub.2 --CH.sub.2 --X-- wherein X represents ##STR1## wherein R is hydrogen or alkyl and R' is alkyl and to the preparation of these compounds which find utility as silver halide complexing agents. This application is also concerned with cycloalkanes containing the moiety ##STR2## useful as intermediates in the preparation of the aforementioned compounds. Also included within the confines of this disclosure are the 2-thioether-substituted derivatives of certain of the above-identified cycloalkanes and with the synthesis of all of these compounds.
    Type: Grant
    Filed: February 2, 1977
    Date of Patent: August 15, 1978
    Assignee: Polaroid Corporation
    Inventors: David H. Evans, Richard B. Greenwald