Method and apparatus for low-loss signal transmission

• US 7,315,678 B2
• Filed: 12/13/2005
• Issued: 01/01/2008
• Est. Priority Date: 12/13/2004
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Fraser, Scott, Shimabukuro, Fred, Siegel, Peter, Yeh, Cavour
• Primary Examiner(s): Font; Frank G.
• Assistant Examiner(s): LAM, HUNG Q
• Application Number:
  US11/300,639
• Publication Number:
  US 20060165360A1
• Time in Patent Office: 749 Days
• Field of Search: 385/117, 385/123, 385/125, 333/239, 333/242, 333/248
• US Class Current: 385/125
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: G02B 6/02328 Hollow or gas filled core
• CPC Class Codes: G02B 6/02347 Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding
• CPC Class Codes: G02B 6/02361 Longitudinal structures forming multiple layers around the core, e.g. arranged in multiple rings with each ring having longitudinal elements at substantially the same radial distance from the core, having rotational symmetry about the fibre axis
• CPC Class Codes: G02B 6/032 with non solid core or cladding G02B6/02295 takes precedence
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00

Abstract

The present invention relates to the field of radio-frequency (RF) waveguides. More specifically, the present invention pertains to a method and apparatus that provides ultra-low-loss RF waveguide structures targeted between approximately 300 GHz and approximately 30 THz. The RF waveguide includes a hollow core and a flexible honeycomb, periodic-bandgap structure surrounding the hollow core. The flexible honeycomb, periodic-bandgap structure is formed of a plurality of tubes formed of a dielectric material such as of low-loss quartz, polyethylene, or high-resistivity silicon. Using the RF waveguide, a user may attach a terahertz signal source to the waveguide and pass signals through the waveguide, while a terahertz signal receiver receives the signals.

Claims

1. A low-loss RF waveguide, comprising:

a hollow core;

a flexible honeycomb, periodic-bandgap fiber surrounding the hollow core, wherein the low-loss RF waveguide is formed to operate in a range of approximately 300 GHz to approximately 30 THz; and

a dielectric ribbon-guide positioned within the hollow core such that the hollow core has a first cross-sectional dimension and a second cross-sectional dimension, wherein the first cross-sectional dimension is not equal to the second cross-sectional dimension.

2. A low-loss RF waveguide as set forth in claim 1, wherein the flexible honeycomb, periodic-bandgap fiber comprises a plurality of tubes having approximately equal cross-sectional geometry.

3. A low-loss RF waveguide as set forth in claim 2, wherein the tubes are formed of a material selected from a group consisting of low-loss quartz, polyethylene, and high-resistivity silicon.

4. A low-loss RF waveguide as set forth in claim 1, wherein the hollow core is over-moded.

5. A low-loss RF waveguide as set forth in claim 1, wherein the flexible honeycomb, periodic-bandgap fiber is composed of material a selected from a group consisting of low-loss quartz, polyethylene, and high-resistivity silicon.

6. A low-loss RF waveguide as set forth in claim 1, wherein the hollow core has a substantially circular cross-section.

7. A low-loss RF waveguide as set forth in claim 1, further comprising a conical feedhorn attached with the hollow core.

8. A low-loss RF waveguide, comprising:

a hollow core;

a flexible honeycomb, periodic-bandgap fiber surrounding the hollow core;

a dielectric ribbon-guide positioned within the hollow core such that the hollow core has a first cross-sectional dimension and a second cross-sectional dimension, wherein the first cross-sectional dimension is not equal to the second cross-sectional dimension; and

wherein the low-loss RF waveguide is formed to operate in a range of approximately 300 GHz to approximately 30 THz;

wherein the flexible honeycomb, periodic-bandgap fiber comprises a plurality of tubes having approximately equal cross-sectional geometry;

wherein the tubes are formed of a material selected from a group consisting of low-loss quartz, polyethylene, and high-resistivity silicon;

wherein the hollow core is over-moded; and

wherein the hollow core has a substantially circular cross-section.

9. A fiberscope comprising:

a low-loss RF waveguide, comprising;

a hollow core;

a flexible honeycomb, periodic-bandgap fiber surrounding the hollow core, wherein the low-loss RF waveguide operates in a range of approximately 300 GHz to approximately 30 THz;

a dielectric ribbon-guide positioned within the hollow core such that the hollow core has a first cross-sectional dimension and a second cross-sectional dimension, wherein the first cross-sectional dimension is not equal to the second cross-sectional dimension; and

a terahertz signal source coupled with the low-loss RF waveguide.

10. A fiberscope as set forth in claim 9, further comprising a conical feedhorn attached with the hollow core and positioned between the low loss-RF waveguide and the terahertz signal source.

11. A fiberscope as set forth in claim 10, further comprising:

a beam splitter located within the low-loss RF waveguide; and

a terahertz signal receiver coupled with the beam splitter.

12. A method for guiding RF signals, the method comprising acts of:

forming a flexible honeycomb, periodic-bandgap fiber around a hollow core; and

positioning a dielectric ribbon-guide within the hollow core such that the hollow core has a first cross-sectional dimension and a second cross-sectional dimension, wherein the first cross-sectional dimension is not equal to the second cross-sectional dimension;

resulting in a low-loss RF waveguide such that the RF waveguide is operable for receiving RF signals in the range of approximately 300 GHz to approximately 30 THz.

13. A method as set forth in claim 12, wherein the act of forming includes an act of arranging tubes of approximately equal size to form the flexible honeycomb, periodic-bandgap fiber.

14. A method as set forth in claim 13, wherein the act of arranging includes an act of selecting the tubes formed of a material selected from a group consisting of low-loss quartz, polyethylene, and high-resistivity silicon.

15. A method as set forth in claim 12, wherein the act of forming includes an act of manufacturing the flexible honeycomb, periodic-bandgap fiber from a material selected from a group consisting of low-loss quartz, polyethylene, and high-resistivity silicon.

16. A method as set forth in claim 12, wherein the act of forming further includes an act of arranging the flexible honeycomb, periodic-bandgap fiber such that the hollow core has a circular cross-section.

17. A method as set forth in claim 12, further comprising an act of coupling a terahertz signal source to the low-loss RF waveguide.

18. A method as set forth in claim 17, further comprising an act of coupling a conical feedhorn between the terahertz signal source and the low-loss RF waveguide such that the conical feedhorn fits into the hollow core.

19. A method as set forth in claim 12, further comprising acts of:

inserting a beam splitter into the low-loss RF waveguide; and

coupling a terahertz signal receiver to the beam splitter.

20. A method of imaging, the method comprising acts of:

utilizing a low-loss RF waveguide, where the low-loss RF waveguide comprises;

a hollow core;

a flexible honeycomb, periodic-bandgap fiber surrounding the hollow core; and

a dielectric ribbon-guide positioned within the hollow core such that the hollow core has a first cross-sectional dimension and a second cross-sectional dimension, wherein the first cross-sectional dimension is not equal to the second cross-sectional dimension;

passing a signal having a frequency in the range of approximately 300 GHz to approximately 30 THz into the low-loss RF waveguide;

reflecting the signal off of an object, resulting in a reflected signal; and

receiving the reflected signal.

21. A method as set forth in claim 20, wherein the act of receiving the reflected signal further comprises acts of:

utilizing a beam splitter inserted into the low-loss RF waveguide; and

receiving the reflected signal with a receiver coupled with the beam-splitter.