Switched multi-beam antenna

• US 20050237258A1
• Filed: 04/12/2005
• Published: 10/27/2005
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: Airgain Incorporated
• Original Assignee: Airgain Incorporated
• Inventors: Nagaev, Farid IBragimovich, Abramov, Oleg Yurievich, Robison, David B., Visuri, Pertti J., Shamblin, Jeffrey K.
• Granted Patent: US 7,215,296 B2
• Time in Patent Office: Days
• US Class Current: 343/834
• CPC Class Codes: H01Q 19/10 using reflecting surfaces
• CPC Class Codes: H01Q 19/106 using two or more intersecting plane surfaces, e.g. corner reflector antennas
• 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 9/32 Vertical arrangement of element H01Q9/40 takes precedence
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An antenna assembly includes a common reflector and multiple monopole type antenna elements positioned on a ground plane and fed with a switch assembly. The switch assembly is capable of feeding individual antennas as well as combining multiple antennas for improved radiation pattern coverage. Multiple antenna elements are placed around the common reflector to cover sectors of space around the antenna assembly to provide transmission and reception of radio frequency (RF) signals for mobile communication devices in a wireless network. The ground plane can be grounded or capacitively coupled to an existing circuit board or metal surface, allowing for reduced ground plane dimensions.

Claims

1. An antenna system comprising:

a reflective layer having an upper surface and a lower surface;

a plurality of antenna elements proximate the upper surface of the reflective layer;

one or more reflectors electrically coupled to the reflective layer and positioned to operate as a reflector for each of the plurality of antenna elements; and

a switch coupled to each of the plurality of antenna elements and configured to select an active state or inactive state for each of the plurality of antenna elements.

2. The system of claim 1 wherein the reflective layer comprises a primary reflective surface to which the plurality of antenna elements are located proximate and a secondary reflective surface.

3. The system of claim 1 wherein each of the plurality of antenna elements comprises:

a center section coupled to the switch at a first end of the center section proximate the reflective layer;

a top section extending from a second end of the center section opposite the first end of the center section;

an inductive section extending from the reflective layer to the top section; and

a capacitive section extending from the top section towards the reflective layer.

4. The system of claim 1 further comprising one or more directors.

5. The system of claim 4 wherein the one or more directors are located on the lower surface of the reflective surface.

6. The system of claim 4 wherein the one or more directors are located on the upper surface of the reflective surface.

7. The system of claim 2 further comprising a plurality of electrically conductive standoffs coupling the primary reflective surface to the secondary reflective surface.

8. The system of claim 1 wherein the switch is configure to select an active state for more than one antenna element at one time.

9. The system of claim 1 further comprising a radio coupled to the switch.

10. The system of claim 9 wherein the radio is located proximate the lower side of the reflective surface.

11. An antenna system comprising:

a base layer;

a ground plane formed on the base layer and having an upper surface and a lower surface proximate the base layer;

a plurality of antenna elements coupled to the base proximate the upper surface of the ground plane and extending outwardly from the ground plane;

a reflector electrically coupled to the ground plane and positioned to operate as a reflector for each of the plurality of antenna elements; and

a switch on the base on a side opposite to the plurality of antenna elements, coupled to each of the plurality of antenna elements and configured to select an active state or inactive state for each of the plurality of antenna elements;

wherein each of the monopole antenna elements in cooperation with the reflector has a direction of transmission.

12. The system of claim 11 further comprising a secondary reflective surface electrically coupled to the ground plane.

13. The system of claim 11 wherein each of the plurality of antenna elements comprises:

a center section coupled to the switch at a first end of the center section proximate the ground plane;

a top section extending from a second end of the center section opposite the first end of the center section;

an inductive section extending from the ground plane to the top section; and

a capacitive section extending from the top section towards the ground plane.

14. The system of claim 11 further comprising one or more directors.

15. The system of claim 14 wherein the one or more directors are located on the lower surface of the ground plane.

16. The system of claim 14 wherein the one or more directors are located on the upper surface of the ground plane.

17. The system of claim 12 further comprising a plurality of electrically conductive standoffs coupling the ground plane to the secondary reflective surface.

18. The system of claim 11 wherein the switch is configure to select an active state for more than one antenna element at one time.

19. The system of claim 11 further comprising a radio coupled to the switch.

20. The system of claim 19 wherein the radio is located on the base proximate the lower side of the ground plane.

21. A communication device comprising:

a base layer;

a reflective layer formed on the base layer and having an upper surface and a lower surface;

a plurality of antenna elements proximate the upper surface of the reflective layer;

one or more reflectors electrically coupled to the reflective layer and positioned to operate as a reflector for each of the plurality of antenna elements;

a radio configured to transmit a radio frequency signal;

a switch coupled the radio and to each of the plurality of antenna elements and configured to select an active state or inactive state for each of the plurality of antenna elements in response to a control signal; and

a controller coupled to the switch and configured generate a control signal to control the switch.

22. A method of manufacturing an antenna assembly comprising:

providing a base layer having an upper surface and a lower surface;

forming a primary reflective surface on the base layer;

providing a plurality of antenna elements proximate the upper surface of the base layer;

providing one or more reflectors proximate the upper surface of the base layer positioned to operate as a reflector for each of the plurality of antenna elements and electrically coupling the one or more reflectors to the primary reflective surface; and

coupling a switch, configured to select an active state or inactive state for each of the plurality of antenna elements in response to a control signal, to each of the plurality of antenna elements.

23. The method of claim 22 further comprising matching the impedance of each of the plurality of antenna elements to the switch.

24. The method of claim 22 adjusting the impedance of each of the plurality of antenna elements with respect to the switch such that the mismatch loss is equal for the cases when one of the plurality of antenna elements in the active state and when two of the plurality of antenna elements are in the active state.

25. The method of claim 23 further comprising adjusting the impedance of an antenna element by shorting one or more impedance tuning pads to the antenna element.

26. The method of claim 23 further comprising shorting one or more impedance tuning pads to each other.

27. The method of claim 22 further comprising electrically coupling a secondary reflective surface to the primary surface.

28. An antenna system comprising:

a base having an upper surface and a lower surface;

a plurality of antenna elements coupled to the base;

one or more reflectors electrically coupled to the reflective layer and positioned to operate as a reflector for each of the plurality of antenna elements; and

a switch coupled to each of the plurality of antenna elements and configured to select an active state or inactive state for each of the plurality of antenna elements.

29. The system of claim 28 wherein each of the antenna elements is a dipole.