Log periodic dipole antenna having an interior centerfeed microstrip feedline

• US 6,133,889 A
• Filed: 01/12/1998
• Issued: 10/17/2000
• Est. Priority Date: 07/03/1996
• Status: Expired due to Term

• Current Assignee: Radio Frequency Systems Incorporated (Amphenol Corporation)
• Original Assignee: Radio Frequency Systems Incorporated (Amphenol Corporation)
• Inventors: Yarsunas, George D., Powell, Charles M.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): CHEN, SHIH CHAO
• Application Number:
  US09/005,749
• Time in Patent Office: 1,009 Days
• Field of Search: 343/792.5, 343/793, 343/794, 343/795, 343/813, 343/700 MS
• US Class Current: 343/792.5
• CPC Class Codes: H01Q 11/10 Logperiodic antennas H01Q11/08 takes precedence
• CPC Class Codes: H01Q 21/0006 Particular feeding systems
• CPC Class Codes: H01Q 21/10 Collinear arrangements of substantially straight elongated conductive units

Abstract

The invention provides a log periodic dipole antenna having a microstrip center feedline and a log periodic hourglass dipole assembly. The microstrip center feedline means responds to an input radio signal for providing a microstrip center feed radio signal. The log periodic hourglass dipole assembly responds to the microstrip feed radio signal, for providing a log periodic hourglass dipole antenna radio signal.

Claims

1. A log periodic dipole antenna (10), comprising:

(a) at least one log periodic dipole assembly (14,

     16) having two dipole strips (26, 28, 30,

     32) with a dipole strip connector (46) therebetween; and

(b) a microstrip feedline (18) having a centerfeed conductor (18C) arranged between the two dipole strips (26, 28, 30,

     32) and coupled to said dipole strip connector (46).

2. The log periodic antenna (10) according to claim 1,

wherein said centerfeed conductor (18C) is arranged between said two dipole strips (26, 28, 30, 32).

3. The log periodic antenna (10) according to claim 1,

wherein said dipole strip connector (46) electrically connects one of said two dipole strips (26, 28, 30, 32) to said centerfeed conductor (46).

4. The log periodic antenna (10) according to claim 1,

wherein each of said two dipole strips (26, 28, 30, 32) includes a plurality of alternating radiating elements (34).

5. The log periodic antenna (10) according to claim 4,

wherein each log periodic dipole assembly (14, 16) includes a plurality of dipoles, each dipole being formed by a pair of adjacent alternating radiating elements (34) on said two dipole strips (26, 28, 30, 32).

6. The log periodic antenna (10) according to claim 5,

wherein said plurality of dipoles includes five dipoles, and said dipole strip connector (46) is arranged at a midpoint of said two dipole strips (26, 28, 30, 32) near a fourth dipole.

7. The log periodic antenna (10) according to claim 1,

wherein said log periodic antenna (10) further comprises a reflector (12), and

wherein said microstrip feedline (18) has at least one microstrip mounting portion (18A) arranged on said reflector (12).

8. The log periodic antenna (10) according to claim 7,

wherein each of said two dipole strips (26, 28, 30, 32) includes an L-shaped base (30B, 32B) arranged on said reflector (12).

9. The log periodic antenna (10) according to claim 5,

wherein said plurality of dipoles includes five dipoles,

wherein said two dipole strips (26, 28, 30, 32) include a nonconducting spacer (38) for providing electrically insulated structural support for each dipole assembly (14, 16),

said nonconducting spacer (38) being arranged adjacent to a second and third dipole.

10. The log periodic antenna (10) according to claim 7, wherein said microstrip feedline (18) includes an input feed portion (18B) arranged on said reflector (12) and connected to an input connector (40) for receiving an input radio signal.

11. The log periodic antenna (10) according to claim 1,

wherein said log periodic antenna (10) further comprises a second log periodic dipole assembly (14, 16) having two dipole strips (26, 28, 30, 32) with a second dipole strip connector (46) therebetween, and

wherein said microstrip feedline (18) includes a second centerfeed conductor (18B) coupled to said second dipole strip connector (46).

12. The log periodic antenna (10) according to claim 11,

wherein said second centerfeed conductor (46) is arranged between said two dipole strips (26, 28, 30, 32) of said second log periodic dipole assembly (14, 16).

13. A center fed log periodic dipole antenna (10) comprising:

A) a reflector (12) for shaping the radiating pattern of said center fed log periodic dipole antenna (10);

B) at least one dipole assembly (14) attached to said reflector (12), said at least one dipole assembly (14) including,

i) a first dipole strip (26) having a front end and an "L" shaped base (26B), said "L" shaped base (26B) of said first dipole strip (26) being attached to said reflector (12),

ii) a plurality of first radiating elements (34) of varying lengths integrally formed with and appending from said first dipole strip (26),

iii) a second dipole strip (28) disposed adjacent to and parallel with said first dipole strip (26), said second dipole strip (28) having a front end and an "L" shaped base (28B), said "L" shaped base (28B) of said second dipole strip (28) being attached to said reflector (12), and

iv) a plurality of second radiating elements (34) of varying lengths integrally formed with and appending from said second dipole strip (28),

said pluralities of first and second radiating elements (34) being arranged to form a plurality of dipoles having a 180 degree phase shift between successive radiating elements; and

C) a microstrip feedline (18) attached to said reflector (12) and including at least one centerfeed conductor (18C), each of said at least one centerfeed conductors (18C) corresponding to each of said at least one dipole assemblies (14,

     16), each of said at least one centerfeed conductors (18C) further being disposed between said first and second dipole strips (26,

     28) of its corresponding dipole assembly (14,

     16) and electrically connected to one of said dipole strips (26,

     28) at a point between said front end and said "L" shaped base (26B, 28B) of said dipole strip (26,

     28).

14. The center fed log periodic dipole antenna (10) of claim 13,

wherein the number of said plurality of first radiating elements (34) is five (5), the first and shortest of said first plurality of radiating elements (34) being disposed near said front end of said first dipole strip (26), the fifth and longest of said first plurality of radiating elements (34) being disposed near said "L" shaped base (26B) of said first dipole strip (26), the remaining of said plurality of first radiating elements (34) being arranged in order by increasing lengths between said first and fifth of said plurality of first radiating elements (34), and wherein the number of said plurality of second radiating elements (34) is five (5), the first and shortest of said second radiating elements (34) being disposed near said front end of said second dipole strip (28), the fifth and longest of said second plurality of radiating elements (34) being disposed near said "L" shaped base (28B) of said second dipole strip (28), the remaining of said plurality of second radiating elements (34) being arranged in order by increasing lengths between said first and fifth of said plurality of second radiating elements (34).

15. The center fed log periodic dipole antenna (10) of claim 14,

wherein each of said at least one centerfeed conductors (46) is electrically connected to one of said dipole strips (26, 28, 30, 32) at a fourth radiating element (34).

16. A log periodic dipole antenna (100, 200), comprising:

(a) a microstrip feedline (118) having a centerfeed conductor (148, 220a, 222a); and

(b) at least one log periodic hourglass dipole assembly (114, 116, 220,

     222) having two hourglass dipole strips (20, 126,

     128) with a dipole strip connector (146, 220b, 222b), the microstrip feedline (118) being arranged between the two hourglass dipole strips (20, 126,

     128), the dipole strip connector (146, 220b, 222b) being coupled to the centerfeed conductor (148, 220a, 222a) of the microstrip feedline (118).

17. The log periodic antenna (100, 200) according to claim 16, wherein the centerfeed conductor (148, 220a, 222a) is arranged between the two hourglass dipole strips (20, 126, 128).

18. The log periodic antenna (100, 200) according to claim 16, wherein the dipole strip connector (146, 220b, 222b) electrically connects one of the two hourglass dipole strips (20, 126, 128) to the centerfeed conductor (148, 220a, 222a).

19. The log periodic antenna (100, 200) according to claim 16, wherein each of the two hourglass dipole strips (20, 126, 128) includes a plurality of alternating radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)).

20. The log periodic antenna (100, 200) according to claim 19, wherein each log periodic hourglass dipole assembly (114, 116, 220, 222) includes a plurality of hourglass dipoles (115, 117, 119, 121), each being formed by a pair of adjacent alternating radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)) on said two hourglass dipole strips (20, 126, 128), and a shortest one of the plurality of radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)) is arranged in the middle of the hourglass dipole assembly (114, 116, 220, 222).

21. The log periodic antenna (100, 200) according to claim 20, wherein said plurality of hourglass dipoles (115, 117, 119, 121) includes five radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)), and said dipole strip connector (146, 220b, 222b) is arranged at a midpoint of said two hourglass dipole strips (20, 126, 128) near a fourth arm (128(d)).

22. The log periodic antenna (100, 200) according to claim 16, wherein the log periodic antenna (100, 200) further comprises a reflector (112);

and

wherein the microstrip feedline (118) has at least one microstrip mounting portion (unlabelled) arranged on said reflector (112).

23. The log periodic antenna (100, 200) according to claim 22, wherein the microstrip feedline (118) includes an input feed portion (unlabelled) arranged on the reflector (112) and connected to an input connector (unlabelled) for receiving the input radio signal.

24. The log periodic antenna (100, 200) according to claim 16, wherein the microstrip feedline (118) includes a second centerfeed conductor (222a);

and

wherein the log periodic antenna (100,

     200) further comprises a second log periodic hourglass dipole assembly (114, 116, 220,

     222) having two hourglass dipole strips (20, 126,

     128) with a second hourglass dipole strip connector (146, 220b, 222b) coupled to the second centerfeed conductor (148, 220a, 222a).

25. The log periodic antenna (100, 200) according to claim 24,

wherein the second centerfeed conductor (222a) is arranged between the two hourglass dipole strips (20, 126, 128) of the second log periodic hourglass dipole assembly (114, 116, 220, 222).

26. A log periodic dipole antenna (100, 200) comprising:

(a) microstrip center feedline means (118), responsive to an input radio signal for providing a microstrip center feed radio signal;

(b) a log periodic hourglass dipole assembly (114, 116, 220,

     222), responsive to the microstrip feed radio signal for providing a log periodic hourglass dipole antenna radio signal; and

the microstrip center feedline (118) being arranged between the log periodic hourglass dipole assembly (114, 116, 220,

     222).

27. The log periodic antenna (100, 200) according to claim 26, wherein the log periodic hourglass dipole assembly (114, 116, 220, 222) includes a plurality of hourglass dipoles (115, 117, 119, 121), each being formed by a pair of adjacent alternating radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)) on two hourglass dipole strips (20, 126, 128), and a shortest one (128(c)), of the plurality of radiating elements (128(a), 128(b), 128(c), 128(d), 128(e)) is arranged in the middle of the hourglass dipole assembly (114, 116, 220, 222).

28. The log periodic antenna (100, 200) according to claim 26, wherein the input signal is a radio signal having a Personal Communication Systems (PCS) frequency.

29. The log periodic antenna (100, 200) according to claim 28, wherein the Personal Communication Systems (PCS) frequency is in a frequency range of 1.850-1.990 Gigahertz.

30. The log periodic antenna (100, 200) according to claim 26, wherein the microstrip center feed means (118) is a top fed microstrip transmission system.

31. The log periodic antenna (100, 200) according to claim 30, wherein the log periodic hourglass dipole assembly (114, 116, 220, 222) is coupled to the top fed microstrip transmission system by a connector (146, 220b, 222b) and a fastener (220b, 222b).