Patent Issued for Terahertz (THz) Reverse Micromagnetron

http://www.hispanicbusiness.com/2014/1/15/patent_issued_for_terahertz_thz_reverse.htm

By a News Reporter-Staff News Editor at Electronics Newsweekly -- The United States of America as represented by the Secretary of the Navy (Washington, DC) has been issued patent number 8624497, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Larraza, Andres (Prunedale, CA); Wolfe, David M. (Texarkana, TX); Catterlin, Jeffrey K. (Salinas, CA).

This patent was filed on April 22, 2013 and was published online on January 7, 2014.


From the background information supplied by the inventors, news correspondents obtained the following quote: "The present invention relates generally to apparatus for producing terahertz (THz) radiation. More specifically, the present invention relates to a microelectromechanical system (MEMS)-based reverse magnetron apparatus for producing THz radiation.

"Most current sources of THz radiation are either very dim (e.g. nonlinear down conversion of optical lasers generate typically nanowatt (nW) outputs), very inefficient, or both (e.g. far infrared lasers have a power output in the THz region of few milliwatts (mW) but efficiencies of about 0.01%). Such conventional THz radiation sources are described in P. H. Siegal, 'THz Technology: An Overview', International Journal of High Speed Electronics and Systems, Vol. 13, No. 2 (2003), which is herein incorporated by reference.

"Quantum cascade lasers can be as bright as 50 mW, but they require cryogenic cooling. Unfortunately, other apparatus capable of generating intense sources of THz radiation are uniformly bulky and difficult to transport (e.g. free electron laser and synchrotron radiation sources).

"Magnetrons have featured prominently in the production of intense microwave radiation, as described in, for example,Victor L. Granatstein and Igor Alexeff, ed., High Power Microwave Sources, Boston: Artech, 1987, herein incorporated by reference. While the external configurations of different conventional magnetrons vary, the basic internal structures are generally the same--these include a central filament/cathode, an outside anode cylinder concentric to the cathode, an antenna, and magnets. The motion of electrons is due to the combined influence of cross electric (radial) and magnetic (axial) fields. In this case, the radiation frequency is near to the cyclotron frequency and amplification is achieved as the whirling cloud of electrons, influenced by the high voltage and the strong magnetic field, forms a rotating pattern that resembles the spokes in a spinning wheel and interacts with an alternating current flow in the resonant cavities configured at the inner surface of the anode. In order to achieve radiation frequencies in the THz region, unrealistically large magnetic fields, of several Tesla, are required.

"U.S. Pat. No. 7,274,147, issued to Shim et al., describes a MEMS-based apparatus, using a miniaturized magnetron and claims to generate THz radiation. In Shim et al. an anode block concentrically surrounds a cathode unit and the electrons spiral outward. The large magnetic field requirements for operation of this device in the THz region make this apparatus impractical."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "In accordance with one embodiment, a terahertz (THz) reverse micromagnetron includes: a cathode ring having a central void; and an anode post centrally located within the central void of the cathode ring, wherein application of an applied voltage between the cathode ring and the anode post causes field-emitted electrons to be accelerated radially inwards producing radiation.

"In accordance with another embodiment, a THz reverse micromagnetron chip includes a plurality of terahertz (THz) reverse micromagnetrons, each THz reverse micromagnetron including: a cathode ring having a central void; and an anode post centrally located within the central void of the cathode ring, wherein application of an applied voltage between the cathode ring and the anode post causes field-emitted electrons to be accelerated radially inwards producing radiation. In one embodiment, the chip has a width of about 1 cm and a length of about 1 cm and includes several hundred of the THz reverse micromagnetrons. In one embodiment, the chip includes a conductive substrate electrically connecting each anode post of the plurality of THz reverse micromagnetrons. In one embodiment, the chip includes a void centrally located on the chip. In one embodiment, this void has an area of at least 1/9 of a total surface area of the chip.

"In accordance with a further embodiment, a terahertz (THz) reverse micromagnetron assembly includes: a chip mount, the chip mount adapted to mount a chip; a chip mounted on the chip mount, the chip including: a plurality of terahertz (THz) reverse micromagnetrons, each THz reverse micromagnetron including: a cathode ring having a central void; and an anode post centrally located within the central void of the cathode ring wherein the chip has a void centrally located on the chip; a a magnet assembly having a first pole and a second pole arranged in a push-pull configuration, wherein each of the first pole and the second pole has a central void, and wherein the chip mount is positioned between the first pole and the second pole of the magnet assembly; a first reflecting mirror and a second reflecting mirror, wherein the first reflecting mirror and the second reflecting mirror form a confocal cavity having a confocal point, further wherein the chip is positioned in the confocal plane of the confocal cavity; and wherein application of an applied voltage between the cathode ring and the anode post causes field-emitted electrons to be accelerated radially inwards producing radiation.

"Embodiments in accordance with the invention are best understood by reference to the following detailed description when read in conjunction with the accompanying drawings."

For the URL and additional information on this patent, see: Larraza, Andres; Wolfe, David M.; Catterlin, Jeffrey K.. Terahertz (THz) Reverse Micromagnetron. U.S. Patent Number 8624497, filed April 22, 2013, and published online onJanuary 7, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=68&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3393&f=G&l=50&co1=AND&d=PTXT&s1=20140107.PD.&OS=ISD/20140107&RS=ISD/20140107