High gain antenna for wireless applications

• US 20040027304A1
• Filed: 05/23/2003
• Published: 02/12/2004
• Est. Priority Date: 04/30/2001
• Status: Active Grant

• Current Assignee: InterDigital Patent Corporation (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Corporation (InterDigital, Inc.)
• Inventors: Chiang, Bing, Lynch, Michael James, Wood, Douglas Harold
• Granted Patent: US 6,864,852 B2
• Time in Patent Office: Days
• US Class Current: 343/810
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/242 Circumferential scanning
• CPC Class Codes: H01Q 3/2641 being secundary elements, e.g. reactively steered
• CPC Class Codes: H01Q 3/446 the radiating element being at the centre of one or more rings of auxiliary elements
• CPC Class Codes: H01Q 9/32 Vertical arrangement of element H01Q9/40 takes precedence

Abstract

An antenna having a central active element and a plurality of passive dipoles surrounding the active element is disclosed. The passive dipoles increase the antenna gain by increasing the radiated energy in the azimuth direction. In another embodiment a plurality of parasitic directing elements extend radially outward from the passive dipoles.

Claims

1. An antenna comprising:

an active element;

a plurality of passive dipoles spaced apart from and circumscribing the active element; and

a controller for selectably controlling the passive dipoles to operate in a reflective or a directive mode.

2. The antenna of claim 1 wherein the antenna directivity is increased along a longitudinal plane through the active element.

3. The antenna of claim 1 wherein antenna radiation is attenuated in a direction perpendicular to the longitudinal plane through the active element.

4. The antenna of claim 1 wherein the controller modifies an effective electrical length of one or more of the plurality of passive dipoles to effectuate the reflective or the directive mode.

5. The antenna of claim 1 wherein each one of the plurality of passive dipoles comprises an upper segment and a lower segment.

6. The antenna of claim 5 wherein the controller modifies an effective electrical length of the upper segment of one or more of the plurality of passive dipoles to effectuate the reflective or the directive mode.

7. The antenna of claim 6 wherein the controller comprises a switching element connected between the upper segment and ground for introducing an impedance between the upper segment and ground.

8. The antenna of claim 7 wherein the switching element selectably introduces one of a first and a second impedance between the upper segment and ground, wherein the first impedance comprises an inductance and the second impedance comprises a capacitance.

9. The antenna of claim 1 further comprising a ground plane proximate a lower end of the active element, wherein the lower segment is formed from a region of the ground plane.

10. The antenna of claim 1 wherein a received or a transmitted signal frequency is the carrier frequency in a wireless system operating according to one of the following standards, code-division multiple access, time division multiple access, IEEE 802.11, Bluetooth, and global system for mobile communications.

11. The antenna of claim 1 wherein the active element and the plurality of passive dipoles are vertically oriented.

12. The antenna of claim 1 wherein the plurality of passive dipoles are radially spaced apart from the active element.

13. The antenna of claim 1 wherein the plurality of passive dipoles are radially spaced an equal distance from the active element.

14. The antenna of claim 1 further comprising a ground, wherein the active element and the plurality of passive dipoles comprise vertically disposed rectangular conductors, wherein each one of the plurality of passive dipoles further comprises an upper and a lower segment, and wherein an upper end of the lower segment is connected to the ground.

15. The antenna of claim 1 further comprising a ground, wherein each one of the plurality of passive dipoles comprises an elongated conductive upper segment switchably connected to the ground and a lower segment in substantial vertical alignment with the upper segment, and wherein an upper end of the lower segment is contiguous with a vertically disposed ground plane extending radially inward in the direction of the active element.

16. The antenna of claim 15 wherein the upper segment is switchably connected to the ground through an impedance.

17. The antenna of claim 1 wherein each one of the plurality of passive dipoles has a physical length, and wherein the antenna transmits or receives an operating signal having a wavelength, and wherein the physical wavelength is less than about a wavelength.

18. The antenna of claim 17 wherein the operating signal comprises a plurality of operating signals, and wherein frequencies of the plurality of operating signals are harmonically related.

19. The antenna of claim 1 further comprising a plurality of parasitic gratings spaced apart from and circumscribing the active element.

20. The antenna of claim 19 wherein each one of the plurality of parasitic gratings is radially aligned with one of the plurality of passive dipoles.

21. The antenna of claim 19 wherein each one of the plurality of parasitic gratings is disposed between two adjacent ones of the plurality of passive dipoles.

22. The antenna of claim 19 wherein the plurality of parasitic gratings are arranged in one or more concentric circles from the active element.

23. The antenna of claim 19 wherein a length of each one of the plurality of parasitic gratings is less than about one-half wavelength at an operating frequency of the antenna.

26. The antenna of claim 19 wherein each one of the plurality of parasitic gratings is vertically oriented.

27. The antenna of claim 19 further comprising a ground, wherein each one of the plurality of parasitic gratings comprises an elongated conductive element shorted to the ground.

28. The antenna of claim 19 further comprising a ring structure for supporting the plurality of parasitic elements.

29. The antenna of claim 28 wherein the ring structure is removably positioned outwardly from and concentric with the plurality of passive dipoles.

30. The antenna of claim 1 further comprising a ground plane surrounding the active element.

31. The antenna of claim 30 wherein the ground plane comprises a substantially horizontal ground plane, and wherein each one of the plurality of passive dipoles comprises an elongated conductive upper segment switchably connected to the horizontal ground plane and a lower segment in substantial vertical alignment with the upper segment, and wherein an upper end of the lower segment is contiguous with a substantially vertical ground plane extending radially inward in the direction of the active element, and wherein the substantially horizontal ground plane is connected to the substantially vertical ground plane.

32. The antenna of claim 1 further comprising a plurality of planar ground structures disposed radially outwardly from the active element, wherein each one of the plurality of passive dipoles comprises an elongated conductive upper segment switchably connected to the ground and a lower segment in substantial vertical alignment with the upper segment, and wherein the lower segment is formed from one of the plurality of planar ground structures.