Switched-resonance antenna phase shifter and phased array incorporation same

• US 20050073461A1
• Filed: 09/28/2004
• Published: 04/07/2005
• Est. Priority Date: 10/02/2003
• Status: Active Grant

• Current Assignee: Toyon Research Corporation
• Original Assignee: Toyon Research Corporation
• Inventors: Norvell, Bill R., York, Robert A., Grace, Michael P.
• Granted Patent: US 7,880,685 B2
• Time in Patent Office: Days
• US Class Current: 343/700.MS
• CPC Class Codes: H01Q 21/0075 Stripline fed arrays H01Q21/065 takes precedence
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence

Abstract

Controlled phase shift in the operation of an RF antenna element is achieved by selectively choosing between different modes of antenna element resonance. Additional phase control resolution is achieved by combining this with other types of phase shifters. Such phase shifters are especially useful within a phased array of RF antenna radiator elements.

Claims

1. An RF antenna phase shifter comprising:

an RF antenna element having plural controllable possible resonant modes of operation, said modes exhibiting phase shifted antenna characteristics relative to one another; and

a controllable circuit connected to selectively cause different ones of said possible resonant modes of operation to occur.

2. An RF antenna phase shifter as in claim 1 further comprising:

a controllable further phase shift circuit connected in series with said antenna element to achieve greater overall controllable phase shifting resolution.

3. An array of plural RF antenna phase shifters as in claim 1 or 2 wherein the antenna elements of the phase shifters also act as antenna elements of a phased array across an array aperture and further comprising:

an array controller providing digital phase control signals to said controllable circuits.

4. A method for providing controlled phase shifts in the operation of an RF antenna element, said method comprising:

providing an RF antenna element having plural controllable possible resonant modes of operation, said modes exhibiting phase shifted antenna characteristics relative to one another; and

selectively causing different ones of said possible resonant modes of operation to occur.

5. A method as in claim 4 further comprising:

selectively causing a further controllable phase shift in series with said antenna element to achieve greater overall controllable phase shifting resolution.

6. A method for providing a controllable phased array using a method as in any of claims 4 or 5 wherein the antenna elements of the phase shifters also act as antenna elements of a phased array across an array aperture and further comprising:

providing digital phase control signals to effect said selectively causing step.

7. An antenna phase shifter comprising:

an RF antenna element having two resonant modes of operation respectively corresponding to two separated feed ports, each said resonant mode being shifted by 180 degrees with respect to the other; and

a controllable RF switch connected to switch an RF feed line between said feed ports in dependence upon an electrical control signal thereby achieving a 0°

/180°

relative phase shift in antenna element operation.

8. An antenna phase shifter as in claim 7 further comprising:

a controllable further phase shifter connected in series with said antenna element to achieve greater overall controllable phase shifting resolution.

9. An antenna phase shifter as in claim 8 wherein:

said RF antenna element comprises a microstrip patch having half-wavelength resonant modes across at least one dimension of the patch.

10. An antenna phase shifter as in claim 9 wherein:

said separated feed points are disposed at internal points disposed between the element and an underlying ground plane at positions symmetrically offset from a center of the element.

11. An antenna phase shifter as in claim 9 wherein:

said separated feed points are disposed at internal points disposed between the element and an underlying ground plane at positions symmetrically offset from a center of the element.

12. An antenna phase shifter as in claim 9 wherein:

said controllable RF switch comprises a first varactor connected to a first of said feed ports and a second varactor connected to a second of said feed ports, said varactors also being dc-connected to separate respective control signal ports and Rf-connected to a common RF feed port.

13. An antenna phase shifter as in claim 12 wherein said control signal ports are configured to supply oppositely-valued varactor bias control signals to said varactors corresponding to an input element bias control signal thereby controlling said varactors to respectively switch between alternate states depending upon corresponding alternate input element bias control signal states.

14. An array of N antenna phase shifters as in any of claims 7, 8, 9, 10, 11, 12 or 13 wherein the antenna elements of the phase shifters also act as antenna elements of a phased array across an array aperture and further comprising:

an array controller providing N binary-valued phase control bits, each of said N bits being connected to control the phase of a respectively corresponding one of said antenna elements.

15. A method for providing controlled phase shifts in the operational mode of an antenna element, said method comprising:

providing an RF antenna element having two resonant modes of operation respectively corresponding to two separated feed ports, each said resonant mode being shifted by 180 degrees with respect to the other; and

controllably switching an RF feed line between said feed ports in dependence upon an electrical control signal thereby achieving a 0°

/180°

relative phase shift in antenna element operation.

16. A method as in claim 15 further comprising:

selectively causing a further controlled phase shift in series with said antenna element to achieve greater overall controllable phase shifting resolution.

17. A method as in claim 16 wherein:

said RF antenna element comprises a microstrip patch having half-wavelength resonant modes across at least one dimension of the patch.

18. A method as in claim 17 wherein:

said separated feed points are disposed at internal points disposed between the element and an underlying ground plane at positions symmetrically offset from a center of the element.

19. A method as in claim 17 wherein:

said separated feed points are disposed at internal points disposed between the element and an underlying ground plane at positions symmetrically offset from a center of the element.

20. A method as in claim 17 wherein:

said controllably switching step is achieved using a first varactor connected to a first of said feed ports and a second varactor connected to a second of said feed ports, said varactors also being dc-connected to separate respective control signal ports and RF-connected to a common RF feed port.

21. A method as in claim 20 wherein said control signal ports are configured to supply oppositely-valued varactor bias control signals to said varactors corresponding to an input element bias control signal thereby controlling said varactors to respectively switch between alternate states depending upon corresponding alternate input element bias control signal states.

22. A method for providing a controllable phased array using a method as in any of claims 15, 16, 17, 18, 19, 20 or 21 for N antenna phase shifters wherein the antenna elements of the phase shifters also act as antenna elements of a phased array across an array aperture and further comprising:

providing N binary-valued phase control bits, each of said N bits being connected to control the phase of a respectively corresponding one of said antenna elements.