Microstrip-fed cylindrical slot antenna

• US 5,955,997 A
• Filed: 05/03/1996
• Issued: 09/21/1999
• Est. Priority Date: 05/03/1996
• Status: Expired due to Term

• Current Assignee: Garmin Corporation (Garmin Limited)
• Original Assignee: Garmin Corporation (Garmin Limited)
• Inventors: Ho, Chien H., Shumaker, Paul K.
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US08/642,506
• Time in Patent Office: 1,236 Days
• Field of Search: 343/767, 343/770, 343/895
• US Class Current: 343/767
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 13/12 Longitudinally slotted cylinder antennas; Equivalent structures

Abstract

A microstrip-fed cylindrical slot antenna is provided for allowing better communication between an object and a satellite. The microstrip-fed cylindrical slot antenna comprises a cylindrical base member; a first conductive coating disposed on the cylindrical base member; at least one slot disposed in the conductive coating, the slot having a helical configuration about the cylindrical base member; and a feed line corresponding to each of the slots, the feed line crossing each respective slot and extending beyond the slot by a distance D.

Claims

1. A microstrip-fed cylindrical slot antenna structure comprising:

a cylindrical base member;

a first conductive coating disposed on said cylindrical base member;

a slot disposed in said conductive coating, said slot having a helical configuration about said cylindrical base member; and

a feed line corresponding to said slot, said feed line crossing said slot in a perpendicular manner and then extending along said slot a distance D in a corresponding helical relationship.

2. The antenna of claim 1, wherein said cylindrical base member comprises a dielectric material.

3. The antenna of claim 1, wherein said cylindrical base member comprises a laminate.

4. The antenna of claim 1, wherein said first conductive coating is connected to an electrical ground and thus forms a ground plane.

5. The antenna of claim 1, further comprising a cap member disposed on a distal end of said cylindrical base member, said cap member having a second conductive coating in electrical communication with said first conductive coating.

6. The antenna of claim 1, wherein said feed line is an electrical open circuit.

7. The antenna of claim 1, wherein said distance D is less than λ

, where λ

is the wavelength of a signal received by said antenna.

8. The antenna of claim 1, wherein said distance D is less than or equal to λ

/4, where λ

is the wavelength of a signal received by said antenna.

9. The antenna of recited in claim 1, wherein said slot is less than or equal to 100 mils wide.

10. The antenna recited in claim 1, wherein said slot having a helical configuration is rolled less than one full turn.

11. The antenna recited in claim 1, wherein said slot having a helical configuration is rolled by 3/4 of a full turn.

12. The antenna recited in claim 1, wherein said slot having a helical configuration is rolled by 1/2 of a full turn.

13. The antenna recited in claim 1, further comprising a feeding network for feeding said feed line before crossing said respective slot.

14. The antenna of claim 13, wherein said feeding network comprises elements selected from the group consisting of:

branch lines, retrace couplers, matched T-splitters and unmatched T-splitters.

15. The antenna recited in claim 1, wherein there are at least four slots having a helical configuration about said cylindrical base member.

16. A microstrip-fed cylindrical slot antenna structure comprising:

a cylindrical base member;

a first conductive coating disposed on said cylindrical base member;

a slot disposed in said conductive coating, said slot having a helical configuration about said cylindrical base member, said slot having a helical configuration being rolled less than one full turn; and

a feed line corresponding to said slot, said feed line crossing said slot in a perpendicular manner and then extending along said slot a distance D in a corresponding helical relationship, said distance D being less than λ

, where λ

is the wavelength of a signal received by said antenna structure.

17. The antenna of claim 16, wherein said cylindrical base member comprises a dielectric material.

18. The antenna of claim 16, wherein said cylindrical base member comprises a laminate.

19. The antenna of claim 16, wherein said first conductive coating is connected to an electrical ground and thus forms a ground plane.

20. The antenna of claim 16, wherein said feed line is an electrical open circuit.

21. The antenna of claim 16, wherein said distance D is less than or equal to λ

/4, where λ

is the wavelength of a signal received by said antenna.

22. The antenna of recited in claim 16, wherein said slot is less than or equal to 100 mils wide.

23. The antenna recited in claim 16, wherein said slot having a helical configuration is rolled by 3/4 of a full turn.

24. The antenna recited in claim 16, wherein said slot having a helical configuration is rolled by 1/2 of a full turn.

25. The antenna recited in claim 16, further comprising a feeding network for feeding said feed lines before crossing said respective slot.

26. The antenna of claim 25, wherein said feeding network comprises elements selected from the group consisting of:

branch lines, retrace couplers, matched T-splitters and unmatched T-splitters.

27. The antenna recited in claim 16, wherein there are at least four slots having a helical configuration about said cylindrical base member.

28. A half-wavelength microstrip-fed cylindrical slot antenna structure comprising;

a cylindrical base member;

a first conductive coating disposed on said cylindrical base member;

a slot disposed in said conductive coating, said slot having a helical configuration about said cylindrical base member, said slot having a helical configuration being rolled by 3/4 of a full turn;

a feed line corresponding to said slot, said feed line crossing said slot in a perpendicular manner and then extending along said slot a distance D in a corresponding helical relationship, said distance D is less than or equal to λ

/4, where λ

is the wavelength of a signal received by said antenna structure; and

a feeding network for feeding said feed line before crossing said slot.

29. The antenna of claim 28, wherein said cylindrical base member comprises a dielectric material.

30. The antenna of claim 28, wherein said cylindrical base member comprises a laminate.

31. The antenna of claim 28, wherein said first conductive coating is connected to an electrical ground and thus forms a ground plane.

32. The antenna of claim 28, further comprising a cap member disposed on a distal end of said cylindrical base member, said cap member having a second conductive coating in electrical communication with said first conductive coating.

33. The antenna of claim 28, wherein said feed line is an electrical open circuit.

34. A quarter-wavelength microstrip-fed cylindrical slot antenna structure comprising;

a cylindrical base member;

a first conductive coating disposed on said cylindrical base member;

a slot disposed in said conductive coating, said slot having a helical configuration about said cylindrical base member, said slot having a helical configuration being rolled by 1/2 of a full turn;

a feed line corresponding to said slot, said feed line crossing said slot in a perpendicular manner and then extending along said slot a distance D in a corresponding helical relationship, said distance D is less than or equal to λ

/4, where λ

is the wavelength of a signal received by said antenna structure; and

a feeding network for feeding said feed line before crossing said slot.

35. The antenna of claim 34, wherein said cylindrical base member comprises a dielectric material.

36. The antenna of claim 34, wherein said cylindrical base member comprises a laminate.

37. The antenna of claim 34, wherein said first conductive coating is connected to an electrical ground and thus forms a ground plane.

38. The antenna of claim 34, wherein said feed line is an electrical open circuit.

39. The antenna of recited in claim 34, wherein said slot is less than or equal to 100 mils wide.

40. The antenna of claim 34, wherein said feeding network comprises elements selected from the group consisting of:

branch lines, retrace couplers, matched T-splitters and unmatched T-splitters.