Electronically steerable sector antenna

• US 20060145921A1
• Filed: 12/30/2004
• Published: 07/06/2006
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yin, Qin-Ye, Jiang, Yan-Sheng, Ranta, Craig Steven
• Granted Patent: US 7,397,425 B2
• Time in Patent Office: Days
• US Class Current: 342/374
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H01Q 1/2258 used with computer equipment
• CPC Class Codes: H01Q 21/20 the units being spaced along or adjacent to a curvilinear path slotted waveguide arrays H01Q21/005; circularly or helically slotted waveguides H01Q21/0062
• 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 3/2682 Time delay steered arrays
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

An electronically steerable antenna system includes a plurality of panels that are coupled together to form an N-sided polygon. Each panel includes a plurality of microstrip conductor patches forming a phased array antenna. In a first embodiment that includes beam steering, each panel can selectively transmit or receive in a direction that is either perpendicular to the panel, or to the left or right of perpendicular, depending upon relative delay line lengths applied to the left and right antennas. A second embodiment omits the beam steering capability for each panel and simply enables only one of the N different panels to be employed for transmitting or receiving a radiofrequency signal in a direction perpendicular to the panel. PIN diodes are preferably used for selecting the panel that is active, and in the first embodiment, for selecting the delay lines used.

Claims

1. A steerable antenna that is selectively controllable in regard to a direction in which the antenna is usable for transmitting or receiving a radio frequency (RF) signal, comprising:

(a) a plurality of panels that are coupled together along edges of the panels, each panel being generally flat and oriented so that an outwardly facing surface of the panel faces in a substantially different direction from outwardly facing surfaces of other of the plurality of panels, each panel including a plurality of conductive microstrips comprising a directional antenna for at least one of transmitting and receiving an RF signal in a direction outwardly from the face of the panel; and

(b) a panel selector switch circuit that is controllable in response to a selector signal to selectively activate one of the plurality of panels for at least one of receiving and transmitting an RF signal, the panel selector switch circuit being coupled to an antenna terminal on each panel.

2. The steerable antenna of claim 1, wherein the plurality of panels are oriented generally vertically and form an N-sided polygon, where N is equal to the number of panels in the plurality of panels.

3. The steerable antenna of claim 1, wherein the panel selector switch circuit includes a plurality of positive-intrinsic-negative (PIN) diode switches.

4. The steerable antenna of claim 1, wherein the conductive microstrips on each panel comprise a plurality of discrete microstrip antennas that comprises a phased array antenna.

5. The steerable antenna of claim 4, further comprising:

(a) a plurality of delay circuits, each of which is selectively coupled to a different one of the plurality of discrete microstrip antennas; and

(b) a delay switch circuit that is selectively controllable to determine which of the plurality of selective delay circuits that provide a desired delay is selected, thereby controlling a direction in which an RF signal is at least one of transmitted and received by the phased array antenna on the panel.

6. The steerable antenna of claim 5, wherein the delay switch circuit includes a plurality of PIN diode switches.

7. The steerable antenna of claim 4, wherein each panel comprises a printed circuit board on which the conductive microstrips comprising the plurality of discrete microstrip antennas are formed as conductive traces.

8. The steerable antenna of claim 4, wherein the plurality of panels and each of the plurality of discrete microstrip antennas are sized for transmitting and receiving signals at radio frequencies used for communicating data over a wireless computing network.

9. The steerable antenna of claim 4, wherein the plurality of discrete microstrip antennas on each panel include a left panel antenna, a center panel antenna, and a right panel antenna, so that:

(a) if the delay selector switch circuit selects a relatively longer delay for the left panel antenna and a relatively shorter delay for the right panel antenna, compared to the delay for the center panel antenna, an RF signal that is one of transmitted and received by the panel is steered to the left of a perpendicular to the panel;

(b) if the delay selector switch circuit selects a relatively longer delay for the right panel antenna and a relatively shorter delay for the left panel antenna, compared to the delay for the center panel antenna, an RF signal that is one of transmitted and received by the panel is steered to the right of a perpendicular to the panel; and

(c) if the delay selector switch circuit selects a common delay for the right panel antenna, the left panel antenna, and the center panel antenna, the direction of an RF signal that is one of transmitted and received by the panel is substantially perpendicular to the panel.

10. The steerable antenna of claim 1, wherein the panel selector switch circuit is controlled in response to a logic level panel selector signal as a function of a desired direction for one of transmitting and receiving an RF signal.

11. The steerable antenna of claim 4, wherein the delay selector switch circuit is controlled in response to a logic level directional selector signal as a function of a desired direction for one of transmitting and receiving an RF signal.

12. A method for controlling a direction in which a steerable antenna is used for at least one of transmitting and receiving a radio frequency (RF) signal, comprising the steps of:

(a) determining a preferred direction for one of transmitting and receiving the RF signal;

(b) selectively activating one of a plurality of generally planar antenna panels that comprise the steerable antenna, wherein the planar antenna panels face in substantially different directions, each panel having a plurality of conductive microstrips that form an antenna on the panel and which are used for one of radiating an RF signal generally outwardly from the outer surface and receiving an RF signal that is directed toward the outer surface of the panel, so that a specific panel of the plurality of panels that faces generally in the preferred direction is selectively activated to one of transmit and receive the RF signal.

13. The method of claim 12, further comprising the step of selectively steering the radio signal that is one of transmitted and received, for the panel that was activated, so that a direction in which the radio signal is one of transmitted and received more closely matches the preferred direction.

14. The method of claim 13, wherein the step of determining the preferred direction for one of transmitting and receiving the RF signal comprises the step of selecting the direction to ensure that substantially a best signal strength for the RF signal that is received, to enable the direction to be controlled in a high multi-path environment where the RF signal that is received may have been reflected from one or more surfaces.

15. The method of claim 13, wherein the step of selectively steering comprises the step of selectively varying a delay with which the radio signal is one of transmitted and received by different ones of a plurality of antenna elements comprising the conductive microstrips on the panel that is activated.

16. The method of claim 15, wherein there are three different antenna elements of conductive microstrips on each panel, including a central antenna element, a left antenna element, and a right antenna element, and wherein the step of selectively steering comprises one of the steps of:

(a) selecting a relatively longer delay in the RF signal conveyed through the left antenna element than through the right antenna element, to steer the direction of the RF signal that is one of transmitted and received to be to the left of a perpendicular to the panel;

(b) selecting a relatively longer delay in the RF signal conveyed through the right antenna element than through the left antenna element, to steer the direction of the RF signal that is one of transmitted and received to be to the right of a perpendicular to the panel; and

(c) selecting a common delay in the RF signal conveyed through the right antenna element, the center antenna element and the left antenna element, to steer the direction of the RF signal that is one of transmitted and received to be substantially perpendicular to the panel.

17. The method of claim 12, wherein the step of selectively activating comprises the step of responding to a panel select signal indicating the panel that should be activated to at least one of transmit and receive the RF signal in the preferred direction.

18. The method of claim 15, wherein the step of selectively varying the delay comprises the step of responding to a delay select signal to more closely match one the preferred direction when one of transmitting and receiving the RF signal.

19. The method of claim 12, further comprising step of automatically repetitively determining the preferred direction and selecting the panel to use for one of transmitting and receiving the RF signal, in response to propagation path changes that affect a signal strength of the RF signal.

20. A wireless network device including a steerable antenna that is selectively controllable in regard to a direction in which the antenna is usable for transmitting or receiving a radio frequency (RF) signal, comprising:

(a) one of a base station and an access point comprising a radio transceiver for both transmitting and receiving wireless RF signals;

(b) a plurality of panels that are coupled together along edges of the panels, each panel being generally flat and oriented so that an outwardly facing surface of the panel faces in a substantially different direction from outwardly facing surfaces of other of the plurality of panels, each panel including a plurality of conductive microstrips comprising a directional antenna for at least one of transmitting and receiving an RF signal in a direction outwardly from the face of the panel; and

(c) a panel selector switch circuit that is controllable in response to a selector signal to selectively activate one of the plurality of panels for at least one of receiving and transmitting an RF signal, the panel selector switch circuit being coupled to an antenna terminal on each panel.