Electric field generator incorporating a slow-wave structure

• US 7,656,167 B1
• Filed: 11/15/2005
• Issued: 02/02/2010
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: McLean, James S.
• Primary Examiner(s): PHAN, HUY Q
• Application Number:
  US11/274,652
• Time in Patent Office: 1,540 Days
• Field of Search: 333/162, 333/163, 333/156, 333/140, 333/4, 333/5, 324/629, 324/632, 324/637
• US Class Current: 324/637
• CPC Class Codes: H01P 9/02 Helical lines

Abstract

An improved E-field generator including a slow-wave transmission line structure is provided herein. In some cases, the improved E-field generator may include an inductively-loaded slow-wave transmission line structure driven by a power source at one end of the structure and terminated by a load at the other end of the structure. In other cases, the improved E-field generator may include a capacitively-loaded slow-wave transmission line structure. In either case, the improved E-field generator provides a frequency-independent, significantly increased electric field at a distance spaced from the generator without altering the dimensions of the generator and/or the input power supplied to the generator. The increase in generated field intensity is achieved by decreasing the phase velocity of the electromagnetic wave propagating along the parallel elements of the generator.

Claims

1. A method for generating an electric field, said method comprising:

arranging a device under test (DUT) within a vicinity of a portion of a transmission line for exposure of the DUT to the generated electric field, wherein the vicinity comprises a distance spaced from the transmission line in a direction orthogonal to a longitudinal axis of the transmission line; and

reducing a phase velocity of a wave traveling into and along the portion of transmission line, as compared to the wave'"'"'s velocity in a conductor coupling the portion of transmission line to a power supply.

2. The method recited in claim 1, wherein said reducing the phase velocity comprises inductively loading the transmission line.

3. A field-directing element for an electric field generation system, said field-directing element comprising a slow-wave transmission line structure, wherein said generation system produces an electric field for exposing a device under test (DUT) arranged within the vicinity of the slow-wave transmission line structure, and wherein said slow-wave transmission line structure localizes the generated electric field a spaced distance away from the transmission line structure in a direction orthogonal to a longitudinal axis of the transmission line structure.

4. The field-directing element recited in claim 3, wherein the slow-wave transmission line structure comprises a capacitively-loaded transmission line.

5. The field-directing element recited in claim 3, wherein the slow-wave transmission line structure comprises an inductively-loaded transmission line.

6. The field-directing element recited in claim 5, wherein the inductively-loaded transmission line comprises a pair of conductors extending along parallel directions.

7. The field-directing element recited in claim 5, wherein the inductively-loaded transmission line comprises a conductor shaped into a helix, and wherein the inductively loaded transmission line is oriented along a longitudinal axis of the helix.

8. The field-directing element recited in claim 7, wherein the helix is arranged around an insulating support structure.

9. The field-directing element recited in claim 7, wherein the inductively-loaded transmission line further comprises a magnetic core arranged within the helix and along the longitudinal axis of the helix.

10. The field-directing element recited in claim 5, wherein the inductively-loaded transmission line comprises a conductor having a conductive surface arranged in proximity to a magnetic material structure, and wherein an impedance of the conductor is increased by the proximity of the magnetic material structure.

11. The field-directing element recited in claim 10, wherein the magnetic material structure comprises ferrite.

12. The field-directing element recited in claim 10, wherein the magnetic material structure comprises one or more rings encircling the conductor.

13. The field-directing element recited in claim 5, wherein the inductively-loaded transmission line comprises a conductor having one or more conductive extensions arranged along a length of the conductor, and wherein the one or more conductive extensions lengthen a current path along the surface of the conductor.

14. The field-directing element recited in claim 13, wherein the one or more conductive extensions comprise conductive rings encircling the conductor.

15. An electric field generation system comprising:

a power source;

a field-directing element coupled to the power source, wherein the field-directing element comprises a slow-wave structure for localizing an electric field generated by the generation system at a location spaced from the slow-wave structure, wherein said localization enables a device under test (DUT) to be placed within a vicinity of the slow-wave structure for exposure of the device to the electric field produced by the generation system.

16. The system recited in claim 15, wherein the slow-wave structure comprises an inductively-loaded transmission line.

17. The system recited in claim 15, further comprising a load coupled to the slow-wave structure, wherein the slow-wave structure is coupled between the power source and the load.

18. The system recited in claim 17, wherein the load comprises a resistive load.

19. The system recited in claim 18, wherein a resistance of the resistive load is substantially equal to a resistance of the power source.

20. The system recited in claim 18, wherein a resistance of the resistive load is greater than a resistance of the power source.

21. The system recited in claim 15, wherein the field-directing element comprises a region of varying diameter adapted to mitigate reflections at a junction between the field-directing element and an adjacent system element.

22. The system recited in claim 21, wherein the adjacent system element comprises the power source, a load or a coaxial line.

23. The system recited in claim 21, wherein the region of varying diameter comprises an insulator of varying diameter.

24. The system recited in claim 21, wherein the region of varying diameter comprises a conductor shaped into a helix of varying diameter.