L-band quadrifilar helix antenna

• US 5,920,292 A
• Filed: 12/20/1996
• Issued: 07/06/1999
• Est. Priority Date: 12/20/1996
• Status: Expired due to Term

• Current Assignee: Blackberry Limited
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: O'Neill, Gregory A. Jr.
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): ST CYR, DANIEL
• Application Number:
  US08/770,399
• Time in Patent Office: 928 Days
• Field of Search: 343/895, 343/894, 343/702, 343/713, 343/796, 343/729
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation

Abstract

Physically small quadrifilar helix antenna systems capable of providing a positive gain, quasi-hemispherical antenna pattern over a relatively broadband frequency range in the L-Band frequency band. The antenna systems according to the present invention generally comprise a quadrifilar helix antenna and at least one antenna feed network, and may further comprise matching means for improving the broadband frequency performance of the antenna. In a preferred embodiment, the elements of the quadrifilar helix antenna which form each bifilar helix are short-circuited at their distal ends, and energy is fed to and induced from the antenna via receive and transmit 90° hybrid couplers which are electrically connected to the bifilar loops of the quadrifilar helix antenna. The antenna systems may further include first and second circuit branches for changing the resonant frequency of the antenna to first and second resonant frequencies corresponding to separate transmit and receive frequency bands, and switches or other disconnection means which are used to electrically isolate the first circuit branch from the antenna during periods when the antenna is receiving a signal and to electrically isolate the second circuit branch from the antenna during periods of transmission.

Claims

1. An antenna system for a handheld transceiver for transmitting signals in the 1626.5 MHz to 1660.5 MHz frequency band and for receiving signals in the 1525 MHz to 1559 MHz frequency band comprising:

(a) a quadrifilar helix antenna having four antenna elements, wherein a diameter of a cylinder defined by said antenna is between 6 and 13 millimeters;

(b) means for coupling signals between said quadrifilar helix antenna and a transceiver; and

(c) at least one reactive matching element coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna

(d) wherein a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 for a continuous bandwidth of at least 25 MHz in both the 1626.5 MHz to 1660.5 MHz and 1525 MHz to 1559 MHz frequency bands.

2. The antenna system of claim 1, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

3. The antenna system of claim 1, wherein a volume required by said quadrifilar helix antenna and said at least one reactive matching element is less than 11 cubic centimeters.

4. The antenna system of claim 1, further comprising a flexible microelectronic substrate, and wherein said quadrifilar helix antenna and said at least one reactive matching element are implemented on said flexible microelectronic substrate.

5. An antenna system for a handheld transceiver for transmitting and receiving radio frequency signals in the L-Band frequency band comprising:

(a) a quadrifilar helix antenna having four antenna elements, wherein an axial length of each element is between 7 and 9 centimeters and a diameter of a cylinder defined by said antenna is between 6 and 13 millimeters, wherein said antenna elements each have an origin and a distal end, and wherein the origin of said first and third antenna elements are coupled to said transceiver, and the origin of said second and fourth antenna elements are coupled to a first reference voltage, and wherein said first and second antenna elements are electrically connected at their distal ends and said third and fourth antenna elements are electrically connected at their distal ends; and

(b) means for coupling signals between said quadrifilar helix antenna and said transceiver.

6. The antenna system of claim 5, wherein said antenna elements are of a length that provides for resonant operation at a frequency in the frequency band over which said handheld transceiver is to operate.

7. The antenna system of claim 5, wherein each antenna element is approximately 0.5 the wavelength (λ

) of operation of said quadrifilar helix antenna.

8. The antenna system of claim 5, wherein said antenna elements are arranged orthogonally and excited in phase quadrature.

9. The antenna system of claim 5, wherein said quadrifilar helix antenna is configured to transmit and receive circularly polarized signals.

10. The antenna system of claim 5, wherein the elements of said quadrifilar helix antenna define a cylinder with a constant diameter which is less than 10% the wavelength (λ

) of operation of said quadrifilar helix antenna.

11. The antenna system of claim 5, wherein a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 for a continuous bandwidth of at least 1.7% of the frequency at which the antenna is designed to operate.

12. The antenna system of claim 11, wherein a volume required by said quadrifilar helix antenna and said matching means is less than 11 cubic centimeters.

13. The antenna system of claim 5, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

14. The antenna system of claim 5, further comprising reactive matching means coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

15. The antenna system of claim 5, further comprising at least one reactive matching element coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

20. The antenna system of claim 15, wherein a volume required by said quadrifilar helix antenna and said matching means is less than 2 cubic centimeters.

21. The antenna system of claim 15, further comprising at least one flexible microelectronic substrate, and wherein said quadrifilar helix antenna and said matching means are implemented on a flexible microelectronic substrate.

16. An antenna system for a handheld user transceiver for receiving radio frequency signals comprising:

(a) a quadrifilar helix antenna having four antenna elements for receiving radio frequency signals in the 1525 MHz to 1559 MHz frequency band with a directivity in excess of 3 dBi for all elevation angles exceeding 45°

, wherein said antenna elements each have an origin and a distal end, and wherein the origin of said first and third antenna elements are coupled to said transceiver, and the origin of said second and fourth antenna elements are coupled to a first reference voltage, and wherein said first and second antenna elements are electrically connected at their distal ends and said third and fourth antenna elements are electrically connected at their distal ends, and wherein said antenna elements are arranged orthogonally and excited in phase quadrature and wherein an axial length of each element is between 7 and 9 centimeters and the diameter of the cylinder defined by said antenna is between 6 and 13 millimeters; and

(b) means for coupling signals between said quadrifilar helix antenna and said transceiver.

17. The antenna system of claim 16, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

18. The antenna system of claim 16, further comprising matching means coupled to the elements of said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

19. The antenna system of claim 18, wherein a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 over the entire 1525 MHz to 1559 MHz frequency band.

22. An antenna system for a handheld user transceiver for transmitting radio frequency signals comprising:

(a) a quadrifilar helix antenna having four antenna elements for transmitting radio frequency signals in the 1626.5 MHz to 1660.5 MHz frequency band with a directivity in excess of 3 dBi for all elevation angles exceeding 45°

, wherein said antenna elements each have an origin and a distal end, and wherein the origin of said first and third antenna elements are coupled to said transceiver, and the origin of said second and fourth antenna elements are coupled to a first reference voltage, and wherein said first and second antenna elements are electrically connected at their distal ends and said third and fourth antenna elements are electrically connected at their distal ends, and wherein said antenna elements are arranged orthogonally and excited in phase quadrature and wherein an axial length of each element is between 7 and 9 centimeters and the diameter of the cylinder defined by said antenna is between 6 and 13 millimeters; and

(b) means for coupling signals between said quadrifilar helix antenna and said transceiver.

23. The antenna system of claim 22, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

24. The antenna system of claim 22, further comprising matching means coupled to the elements of said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

25. The antenna system of claim 24, wherein a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 over the entire 1626.5 MHz to 1660.5 MHz frequency band.

26. The antenna system of claim 25, wherein a volume required by said quadrifilar helix antenna and said matching means is less than 11 cubic centimeters.

27. The antenna system of claim 24, further comprising at least one flexible microelectronic substrate, and wherein said quadrifilar helix antenna and said matching means are implemented on a flexible microelectronic substrate.

28. An antenna system for a handheld transceiver for transmitting and receiving radio frequency signals comprising:

(a) a quadrifilar helix antenna having four antenna elements, wherein an axial length of each element is between 0.37 and 0.48 the wavelength of operation and the diameter of the cylinder defined by said antenna is between 0.03 and 0.07 the wavelength of operation and wherein said antenna elements each have an origin and a distal end, and wherein the origin of said first and third antenna elements are coupled to said transceiver, and the origin of said second and fourth antenna elements are coupled to a first reference voltage and wherein said first and second antenna elements are electrically connected at their distal ends and said third and fourth antenna elements are electrically connected at their distal ends; and

(b) means for coupling signals between said quadrifilar helix antenna and said transceiver.

29. The antenna system of claim 28, wherein said transceiver transmits signals in the 1626.5 MHz to 1660.5 MHz frequency band and receives signals in the 1525 MHz to 1559 MHz frequency band.

30. The antenna system of claim 28, wherein said antenna elements are of a length that provides for resonant operation at a frequency in the frequency band over which said handheld transceiver is to operate.

31. The antenna system of claim 28, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

32. The antenna system of claim 28, further comprising at least one reactive matching element coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

33. A handheld transceiver for transmitting and receiving radio frequency signals in the L-Band frequency band comprising:

(a) a transmitter;

(b) a receiver;

(c) a user interface;

(d) a quadrifilar helix antenna having four antenna elements, wherein an axial length of each element is between 7 and 9 centimeters and the diameter of the cylinder defined by said antenna is between 6 and 13 millimeters and wherein said antenna elements each have an origin and a distal end, and wherein the origin of said first and third antenna elements are coupled to said transceiver and the origin of said second and fourth antenna elements are coupled to a first reference voltage, and wherein said first and second antenna elements are electrically connected at their distal ends and said third and fourth antenna elements are electrically connected at their distal ends; and

(e) means for coupling signals between said quadrifilar helix antenna and said transceiver.

34. The transceiver of claim 33, wherein said antenna elements are of a length that provides for resonant operation at a frequency in the frequency band over which said handheld transceiver is to operate.

35. The transceiver of claim 33, wherein each antenna element is approximately 0.5 the wavelength (λ

) of operation of said quadrifilar helix antenna.

36. The transceiver of claim 33, wherein each of said antenna elements comprises a filar helix with a pitch angle greater than about 55 degrees and less than about 85 degrees.

37. The transceiver of claim 33, wherein said antenna elements are arranged orthogonally and excited in phase quadrature.

38. The transceiver of claim 33, wherein said quadrifilar helix antenna is configured to transmit and receive circularly polarized signals.

39. The transceiver of claim 33, further comprising reactive matching means coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna.

40. The transceiver of claim 39, wherein a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 for a continuous bandwidth of at least 25 MHz in the L-Band frequency band.

41. An antenna system for a handheld transceiver for transmitting and receiving radio frequency signals comprising:

(a) a quadrifilar helix antenna having four antenna elements, wherein a diameter of a cylinder defined by said antenna is between 0.03 and 0.07 of a wavelength corresponding to a frequency at which the antenna is designed to operate;

(b) means for coupling signals between said quadrifilar helix antenna and said transceiver; and

(c) at least one reactive matching element coupled to said quadrifilar helix antenna for increasing the operating bandwidth of said quadrifilar helix antenna so that a voltage standing wave ratio as measured at the output of said transceiver is less than 1.5 for a continuous bandwidth of at least 1.7% of a frequency at which the antenna is designed to operate;

(d) wherein said transceiver is configured to transmit signals in the 1626.5 MHz to 1660.5 MHz frequency band and receive signals in the 1525 MHz to 1559 MHz frequency band.

42. The antenna system of claim 41, wherein said quadrifilar helix antenna has a directivity in excess of 3 dBi for all elevation angles exceeding 45°

over said continuous bandwidth of at least 1.7% of the frequency at which the antenna is designed to operate.

43. The antenna system of claim 41, wherein a volume required by said quadrifilar helix antenna and said matching means is less than 11 cubic centimeters.

44. The antenna system of claim 41, further comprising a flexible microelectronic substrate, and wherein said quadrifilar helix antenna and said at least one reactive matching element are implemented on said flexible microelectronic substrate.

45. The antenna system of claim 41, wherein an axial length of each element is between 0.37 and 0.48 the wavelength of operation.