Patents by Inventor Hunter L. McDowell

Hunter L. McDowell 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: 6236161
    Abstract: A crossed-field device such as a crossed-field amplifier or magnetron has a generally peripheral cathode body portion and an anode which cooperates with a crossed magnetic field to maintain emitted electrons on cycloidal and amplify an rf input signal as it travels to an rf outlet. A control electrode positioned generally at a drift region away from the crossed-field amplification region interrupts the sustained electron emission to shut down the device between working cycles, and an auxiliary electrode positioned internally of the cathode diverts electrons into a gap proximally of the control electrode to reduce the control electrode energy requirements. The cathode is carried by a support structure, and the auxiliary electrode may be a rod axially extending in a counter-bore in the support structure. The auxiliary electrode is dc biased and may advantageously operate at anode potential, thereby obviating the need for any additional power source for the auxiliary electrode.
    Type: Grant
    Filed: February 26, 1999
    Date of Patent: May 22, 2001
    Assignee: Communications & Power Industries, Inc.
    Inventors: Michael L. Tracy, Carl D. Morrill, Hunter L. McDowell
  • Patent number: 4608520
    Abstract: In a crossed-field amplifier tube, an input section of slow-wave circuit is part of the cathode electrode. An output section of slow-wave circuit is part of the anode electrode. The anode circuit is axially displaced from the cathode circuit in the direction of drift of the electron stream so that a non-propagating section of the anode faces at least a part of the propagating cathode circuit.
    Type: Grant
    Filed: July 29, 1983
    Date of Patent: August 26, 1986
    Assignee: Varian Associates, Inc.
    Inventor: Hunter L. McDowell
  • Patent number: 4465984
    Abstract: A meander line slow wave structure mounted on ceramic bars for a microwave evice such as an injected beam crossed-field amplifier includes frequency selective attenuator means which will preferentially attenuate waves at frequencies near and within the stopband of the slow wave structure by the placement of side absorber bars of attenuating material adjacent to the outer side surfaces of a plurality of meander line finger segments. The frequency selective absorber material, in its preferred form, comprises a beryllia and silicon carbide ceramic composition which additionally adapted to accommodate metallic absorber top plates, nichrome films, and slotted side ring configurations.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: August 14, 1984
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventor: Hunter L. McDowell
  • Patent number: 4435689
    Abstract: A broadband attenuator section in a meander line slow wave structure is dlosed for attenuating signals reflected between the output and input of the slow wave structure. The attenuator section comprises a multi-element ceramic support structure intermediate the meander line conductor pattern and the substrate wherein the support elements are comprised of a beryllium oxide-silicon carbide ceramic composition with a taper in the percentage of silicon carbide being provided in the transition region from a loss free section of the slow wave structure to a lossy attenuator section. The taper in percentage involves the use of ceramic support elements arranged in a sequence of 1%, 2% and 5% silicon carbide composition prior to the main attenuator section which is comprised of 10% silicon carbide - 90% beryllium oxide support elements.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: March 6, 1984
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventor: Hunter L. McDowell
  • Patent number: 4342632
    Abstract: A ceramic substrate is metallized by a method including the steps of:(A) chemically cleaning the substrate,(B) sputter etching the chemically cleaned substrate,(C) sputtering a chromium layer of about 200 angstroms in thickness onto substrate,(D) sputtering a molybdenum layer of about 3500 angstroms in thickness onto the chromium layer,(E) sputtering a copper layer of about 25,000 angstroms in thickness onto the molybdenum layer,(F) firing the coated substrate in dry hydrogen at about 1000.degree. C. for about 10 minutes,(G) plating a copper-silver brazing alloy of about 0.0003 inch in thickness onto the copper layer, and(H) firing in dry hydrogen at about 700.degree. C. for about 10 minutes.
    Type: Grant
    Filed: May 1, 1981
    Date of Patent: August 3, 1982
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Werner F. Heim, Hunter L. McDowell
  • Patent number: 4207495
    Abstract: Crossed field amplifier collector efficiency is improved by decreasing the ratio of electron velocities to r.f. signal wave velocity at the output end of the amplifier slow wave circuit. In a preferred embodiment of the invention this is accomplished by tapering the sole emitting cathode so as to increase the cathode-slow wave circuit spacing in the output end of the interaction region prior to the collector. Alternatively, an increasing r.f. signal phase velocity taper can be used to provide the required decreased electron velocities to r.f. signal wave velocity ratio.
    Type: Grant
    Filed: August 30, 1978
    Date of Patent: June 10, 1980
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventor: Hunter L. McDowell