Radio frequency holographic transformer

• US 7,460,084 B2
• Filed: 10/19/2005
• Issued: 12/02/2008
• Est. Priority Date: 10/19/2005
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Upton, Eric L.
• Primary Examiner(s): Wimer; Michael C
• Application Number:
  US11/255,607
• Publication Number:
  US 20070103381A1
• Time in Patent Office: 1,140 Days
• Field of Search: 343/753, 343/754, 343/909
• US Class Current: 343/909
• CPC Class Codes: H01Q 19/067 using a hologram

Abstract

A three-dimensional holographic array of radio-frequency (RF) diffraction gratings, each of which has lengths of conductive and insulating fluid that are selected and adjusted to provide a desired diffraction effect on incident RF radiation. The three-dimensional array functions analogously to an optical hologram, and is programmable to provide desired refraction and focusing effects on multiple RF incident beams, which may be selectively directed to receivers or, if interferers, ignored. Because the gratings employ conductive and insulating fluids, the array can be reprogrammed in near real time to adapt to changes in the incident RF radiation.

Claims

1. A three-dimensional radio-frequency (RF) holographic transformer, comprising:

an array of elemental RF diffraction gratings, each of which comprises selected lengths of electrically conductive material and electrically insulating material arranged in a selected alternating sequence; and

means for programming each of the elemental gratings independently, to vary the lengths of conductive and insulating material contained in each of the elemental gratings in order to achieve a desired effect on one or more RF beams incident on the away of gratings;

wherein the array of gratings is programmable to perform different desired refractive operations on the incident RF beams, each such operation being performed independently of and simultaneously with the others.

2. A three-dimensional RF holographic transformer as defined in claim 1, wherein

each elemental RF diffraction grating comprises:

an elongated tube; and

means for filling the tube with fluid selected from a supply of conductive fluid and a supply of insulating fluid.

3. A three-dimensional RF holographic transformer as defined in claim 2, wherein the means for filling the tube further comprises an electrically actuated fluid valve for selecting a supply of fluid.

4. A three-dimensional RF holographic transformer as defined in claim 2, wherein:

the elemental gratings are formed on a continuous substrate ribbon, which comprises, in addition to the elongated tubes,

an electrically actuated fluid valve coupled to each of the elongated tubes, a first plenum extending along the substrate ribbon to supply conductive fluid to the elongated tubes,

a second plenum extending along the substrate ribbon to supply insulating fluid to the elongated tubes,

a third plenum extending along the substrate ribbon to provide a discharge path for fluids removed from the elongated tubes during reprogramming of the tubes'"'"' contents, and

at least one electrical conductor extending along the substrate ribbon and coupled to electrically controlled fluid valves to provide controlled selection of fluid for each elongated tube either from the first plenum, the second plenum, or a blend of the first and second plenums; and

the substrate ribbon is rolled to form a three-dimensional bundle of the elemental gratings.

5. A three-dimensional RF holographic transformer as defined in claim 4, wherein

each elemental grating comprises, in addition to the elongated tube:

a feed tube supplied from a selected fluid through its fluid valve, wherein the feed tube is smaller in cross section than the elongated tube, and extends though the elongated tube through substantially all of its length;

wherein the feed tube is open at its distal end and the elongated tube is closed at its distal end, and wherein the elemental grating is programmed by drawing selected amounts of conducting and insulating fluid through the feed tube and into the elongated tube, such that the latter becomes filled with selected lengths of conductive fluid, insulating fluid and, if selected, blended proportions of both conductive and insulating fluids.

6. A method for processing radio-frequency (RF) beams in a three-dimensional holographic transformer having an array of independently programmable RF grating elements, the method comprising:

determining by computation the grating configuration needed to effect a transformation of each of one or more RF signals incident on the array;

configuring each elemental grating in an array of such gratings, to comprise selected lengths of conductive and insulating fluids, as arrived at in the determining step; and

adjusting and reconfiguring each elemental grating as necessary to adapt to changing configurations of incident RF signals.

7. A method as define by claim 6,

wherein the step of configuring each elemental grating comprises:

selecting fluid from a supply of conductive fluid, a supply of insulating fluid, or a combination of the two supplies;

pumping selected fluid supplies into an elongated tube, to form therein layers of conductive fluid, insulating fluid and, if selected, a blend of conductive and insulating fluids; and

simultaneously with the pumping step, discharging unwanted fluid from the elongated tube.

8. A three-dimensional radio-frequency (RF) holographic transformer, comprising:

an array of elemental RF diffraction gratings, each of which comprises selected lengths of electrically conductive material and electrically insulating material arranged in a selected alternating sequence; and

an array of electronically controllable switches configured to vary the lengths of electrically conductive material and electrically insulating material contained in each of the elemental RF diffraction gratings in order to achieve a desired diffraction on one or more RF beams incident on the array of elemental RF diffraction gratings.

9. The three-dimensional RF holographic transformer of claim 8, wherein:

each elemental RF diffraction grating of the array of elemental RF diffraction gratings comprises an elongated tube; and

the electrically conductive material comprises an electrically conductive fluid and the electrically insulating material comprises an electrically insulating fluid.

10. The three-dimensional RF holographic transformer of claim 8, wherein the selected alternating sequence of at least one of the elemental RF diffraction gratings of the array of elemental RF diffraction gratings includes at least three selected lengths.