Dual polarized cross bow tie dipole antenna having integrated airline feed

• US 6,028,563 A
• Filed: 07/09/1998
• Issued: 02/22/2000
• Est. Priority Date: 07/03/1997
• Status: Expired due to Fees

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Higgins, Thomas P.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US09/113,045
• Time in Patent Office: 593 Days
• Field of Search: 343/797, 343/798, 343/810, 343/812, 343/813, 343/878, 343/793, 343/795, 343/815, 343/816, 343/817
• US Class Current: 343/797
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 21/16 U-type
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/26 Turnstile or like antennas comprising arrangements of three or more elongated elements disposed radially and symmetrically in a horizontal plane about a common centre

Abstract

A dual polarization antenna for transmitting/receiving polarized radio frequency signals includes a reflector plate that reflects the polarized radio frequency signals and one or more dipole assemblies. Each dipole assembly has two cross bow tie dipoles having radiating arms for transmitting/receiving the polarized radio frequency energy signals at two polarizations, and having U-shaped air-filled transmission feedlines for supporting respective radiating arms and providing the radio frequency signals between the reflector plate and the respective radiating arms. Each U-shaped air-filled transmission feedline includes two legs and respective feed rods arranged in respective legs. Each leg has a rectangular shape with three sides for isolating undesirable radio frequency energy. The radiating arms are triangularly-shaped and have notches dimensioned for minimizing radiation pattern distortion due to undesirable radio frequency coupling between the two cross bow tie dipoles. The dual polarization antenna also has an RF isolation device for coupling RF energy back in a proper phase and magnitude to cancel the undesirable RF energy of the respective opposite polarization. The RF isolation device includes an isolation tree or bar, isolation rails, small thin isolation rods or wires arranged in relation to the dipole assembly, or an isolation strip between positive and negative arms of the cross bow tie dipoles; or a combination of one or more of the above.

Claims

1. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) for transmitting or receiving polarized radio frequency signals, comprising:

a reflector plate (22, 152, 202, 302,

     402) that is a ground plane and that reflects the polarized radio frequency signals;

one or more bow tie assemblies (24;

82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104;

154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176;

204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226;

304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326;

404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426;

     500), each having two cross bow tie dipoles (26,

     28) with radiating arms (40, 42;

60,

     62) for transmitting or receiving the polarized radio frequency signals at two polarizations, each cross bow tie dipoles (26,

     28) also having U-shaped air-filled transmission feedline means (30, 32, 34;

50, 52,

     54) for supporting respective radiating arms (40, 42;

60,

     62) and for providing the polarized radio frequency signals between the reflector plate (22, 152, 202, 302,

     402) and said respective radiating arms (40, 42;

60,

     62).

2. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1, wherein each U-shaped air-filled transmission feedline means (30, 32, 34;

50, 52,

     54) includes two legs (30, 32;

50,

     52) and a respective feed rod (34;

     54) arranged in a respective one of the two legs (30, 32;

50,

     52).

3. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 2, wherein each leg (30, 32;

50,

     52) has a rectangular shape with at least three sides (66, 68,

     70) for isolating undesirable radio frequency energy.

4. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 2, wherein the characteristic impedance of each U-shaped rectangular air-filled transmission feedline means (30, 32, 34;

50, 52,

     54) is substantially the same as the impedance of a respective cross bow tie dipole (26,

     28), and is calculated by the following equation;

##EQU2## where D is a one-sided or open dimension of the respective U-shaped rectangular air-filled transmission feedline means (30, 32, 34;

50, 52,

     54), d is a diameter of a respective feed rod (34;

     54), and h is a distance from a respective single wall of the respective U-shaped rectangular air-filled transmission feedline means (30, 32, 34;

50, 52,

     54) to a respective center of the respective feed rod (34;

     54).

5. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1, wherein the respective radiating arms (40, 42;

60,

     62) include triangularly-shaped arms (40, 42;

60,

     62), each having notches (40a, 40b;

42a, 42b;

60a, 60b;

62a, 62b) dimensioned for minimizing radiation pattern distortion due to undesirable radio frequency coupling between the two cross bow tie dipoles (26,

     28).

6. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 5,

wherein each triangularly-shaped arm has an inner corner (46a) with a 90 degree angle, two outer corners (46b, 46c) having respective 45 degree angles, and a respective side (46d, 46e) in relation to the inner corner (46a) and the two outer corners (46b, 46c), each outer corner (46b, 46c) having a respective symmetrical notch (40a, 40b;

42a, 42b;

60a, 60b;

62a, 62b) cut therein along the respective side (46d, 46e).

7. A dual polarization antenna according (20, 80, 150, 200, 300, 400, 500) to claim 6, wherein each respective symmetrical notch (40a, 40b;

42a, 42b;

60a, 60b;

62a, 62b) has an edge substantially 46f, 46g) parallel to the respective side (46d, 46e).

8. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 7,

wherein each respective side (46d, 46e) has a length (Ls) and each symmetrical notch (40a, 40b;

42a, 42b;

60a, 60b;

62a, 62b) has a corresponding length (Ln) that is substantially equal to the length (Ls) of the respective side (46d, 46e).

9. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 8,

wherein the corresponding length (Ln) of each symmetrical notch (40a, 40b;

42a, 42b;

60a, 60b;

62a, 62b) and the length (Ls) of the respective side (46d, 46e) are dimensioned with a ratio in a range of 1;

3 to 3;

1.

10. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1, wherein the radio signals include a first radio signal and a second radio signal that is independent of the first radio signal, for transmitting or receiving radio signals having orthogonal polarizations.

11. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1, wherein the radio signals include a first radio signal and a second radio signal having a 90 degree phase difference from the first radio signal, for transmitting or receiving circularly polarized radio signals having orthogonal polarizations.

12. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1, wherein the one or more bow tie assemblies (24;

82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104;

154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176;

204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226;

304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326;

404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426;

     500) further comprises a base (29) for mounting on the reflector plate (22, 152, 202, 302,

     402).

13. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 12, wherein the base (29) has a 1/4λ

dipole spacer shorting plate (72) connected to the U-shaped rectangular air-filled transmission feedline means (30, 32, 34;

50, 52,

     54).

14. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 1,

wherein the dual polarization antenna further comprises an RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) for coupling RF energy back to the pairs of cross dipoles (26,

     28) forming the bow tie assemblies (24;

82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104;

154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176;

204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226;

304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326;

404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426;

     500), the RF energy being coupled having a phase and magnitude so as to cancel undesired RF energy coupled between dipoles (26,

     28) of opposite polarization.

15. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 14, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes either (1) one or more isolation trees (180,

     230) or bars (232) arranged in relation to bow tie assemblies (154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176;

204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224,

     226);

(2) one or more isolation rails (328,

     330) arranged alongside the one or more bow tie assemblies (304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326;

404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426;

     500);

(3) one or more small thin isolation rods or wires (430, 432, 434,

     436) arranged in or on a radome (428) that covers the one or more bow tie assemblies (402, 404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424,

     426);

(4) one or more isolation strips (510,

     520) coupled between positive and negative arms (502, 506;

504,

     508) of a bow tie assembly (500);

or (5) a combination of one or more of the above.

16. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes an isolation tree (180;

     230) having a top surface (182) with eight branches (184, 186, 188, 190, 192, 194, 196,

     198) and having two legs (199a, 199b) connected to respective standoffs (199a, 199b) for supporting the same on the reflector plate (152).

17. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes an isolation bar (232) having a flat top surface (234) and having two mounting standoff apertures (236,

     238) for receiving two insulation standoffs (240) for supporting the same on the reflector plate (22, 152, 202, 302,

     402).

18. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15,

wherein the dual polarization antenna (20) has twelve bow tie assemblies (204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226) arranged in a linear array,

wherein the isolation bar (232) is positioned between a fourth and fifth bow tie assembly (218, 220), and

wherein the isolation tree (230) is positioned between a seventh and eighth bow tie assembly (212, 214).

19. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes a side isolation rail (328,

     330) mounted of the reflector plate (302).

20. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes one or more small thin isolation rods or wires (430, 432, 434,

     436) embedded in or arranged on a radome (428) that covers the dual polarization antenna (400).

21. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the one or more small and thin isolation rods or wires (430, 432, 434, 436) are positioned at an angle of about 45 degrees between the one or more bow tie assemblies (404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426).

22. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the one or more small and thin isolation rods or wires (430, 432, 434, 436) have a length in a range of about 55-75 millimeters that determines the magnitude of a return signal that cancels the undesirable RF energy of the respective opposite polarization.

23. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 22, wherein the one or more small and thin isolation rods or wires (430, 432, 434, 436) have a height in a range of about 2.5 to 4.0 inches above the ground plate that determines a phase of a return signal that cancels the undesirable RF energy of the respective opposite polarization.

24. A dual polarization antenna (20, 80, 150, 200, 300, 400, 500) according to claim 15, wherein the RF isolation device (180;

230, 232;

328, 330;

430, 432, 434, 436;

510,

     520) includes means for coupling undesired RF energy having one or more isolation strips (510,

     520), each having;

an insulator (514,

     524) connected between a first dipole arm (502,

     508) and a second dipole arm (504,

     506); and

a thin strip of metal (512,

     522) arranged on the insulator (514,

     524) for coupling the first dipole arm (502,

     508) and the second arm (504,

     506).

25. A dual polarization antenna for transmitting or receiving polarized radio frequency signals, comprising:

a reflector plate that is a ground plane and that reflects the polarized radio frequency signals;

at least one cross dipole assembly, each having two cross dipoles with radiating arms for transmitting or receiving the polarized radio frequency signals at two polarizations, each cross dipole also having U-shape air-filled transmission feedline means for supporting respective radiating arms and for providing the polarized radio frequency signals between the reflector plate and said respective radiating arms; and

an RF isolation device for coupling RF energy back to the pairs of cross dipoles forming the cross dipole assemblies, the RF energy being coupled having a phase and magnitude so as to cancel undesired RF energy coupled between dipoles of opposite polarization.

26. A dual polarization antenna according to claim 25, wherein the RF isolation device includes either (1) one or more isolation trees or bars arranged in relation to cross dipole assemblies;

(2) one or more isolation rails arranged alongside the one or more cross dipole assemblies;

(3) one or more small thin isolation rods, wires or strips arranged in or on a radome that covers the one or more cross dipole assemblies;

or (4) a combination thereof.

27. A dual polarization antenna according to claim 25,

wherein the RF isolation device includes an isolation tree having a top surface with branches and having two legs connected to respective standoffs for supporting the same on the reflector plate.

28. A dual polarization antenna according to claim 25,

wherein the RF isolation device includes an isolation bar having a flat top surface and having at least one mounting standoff apertures for receiving two insulation standoffs for supporting the same on the reflector plate.

29. A dual polarization antenna according to claim 25,

wherein the dual polarization antenna has a multiplicity of cross dipole assemblies arranged in a linear array;

and

wherein the RF isolation device includes an isolation bar positioned between two cross dipole assemblies, and an isolation tree positioned between another cross dipole assemblies.

30. A dual polarization antenna according to claim 25,

wherein the RF isolation device includes a side isolation rail mounted on the reflector plate.

31. A dual polarization antenna according to claim 25,

wherein the RF isolation device includes one or more small thin isolation rods, wires or strips embedded in or arranged on a radome that covers the dual polarization antenna.

32. A dual polarization antenna according to claim 31,

wherein the one or more small and thin isolation rods or wires are positioned at an angle of about 45 degrees between the one or more cross dipole assemblies.

33. A dual polarization antenna according to claim 31,

wherein the one or more small and thin isolation rods or wires have a length in a range of about 55-75 millimeters that determines the magnitude of a return signal that cancels the undesirable RF energy of the respective opposite polarization.