Circularly polarized reflect array using 2-bit phase shifter having initial phase perturbation

• US 6,351,240 B1
• Filed: 09/19/2000
• Issued: 02/26/2002
• Est. Priority Date: 02/25/2000
• Status: Expired due to Term

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Song, Jian, Lee, Lin-Nan, Kay, Stanley E., Karimullah, Khalid
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): NGUYEN, HOANG V
• Application Number:
  US09/664,695
• Time in Patent Office: 525 Days
• Field of Search: 343/700.MS, 343/846, 343/853, 343/829
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 3/38 the phase-shifters being digital
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave

Abstract

An approach for electronically performing beam steering is disclosed. For electronic scanning, an n-bit quantized phase shifting approach is employed at each array element of a phased array antenna. By applying an initial phase bias, either deterministically or randomly, in each of the array elements, the performance of a phased array with n-bit quantization (even with n=2) approaches the performance of a system with no quantization. This approach can be used with linearly polarized or circularly polarized waves. For circularly polarized waves, the 2ⁿ phase shifts required of n-bit quantization are achieved in a manner that provides a simple, low-loss construction, which allows production of a low-cost reflectarray or a flat-plate lens.

Claims

1. A method of performing electronic beam steering using a circular patch having a plurality of taps coupled to a plurality of switches, the method comprising:

controlling the plurality of switches to short an orthogonal pair of the plurality of taps to provide a phase shift, the taps being arranged on the circular patch to provide identical boundary conditions; and

selectively performing at least one of receiving a signal and transmitting the signal.

2. The method according to claim 1, further comprising:

applying a fixed phase bias based upon geometric positioning of the circular patch.

3. The method according to claim 1, wherein the signal in the step of selectively performing is circularly polarized.

4. The method according to claim 1, wherein the signal in the step of selectively performing is linearly polarized.

5. A method of performing electronic beam steering using a circular patch having a plurality of taps coupled to a plurality of switches, the method comprising:

controlling the plurality of switches to short an orthogonal pair of the plurality of taps, the taps being arranged on the circular patch to provide identical boundary conditions;

selectively performing at least one of receiving a signal and transmitting the signal; and

applying a fixed phase bias of a predetermined distribution to the signal, the predetermined distribution being at least one of a deterministic distribution and a random distribution.

6. An antenna apparatus comprising:

a circular patch having a plurality of orthogonal tap pairs arranged on the patch;

a plurality of switches corresponding to the taps, each of the switches being coupled to ground; and

a controller configured to control the switches to short one of the orthogonal tap pairs corresponding to a phase shift of a signal having orthogonal EM (electromagnetic) modes,

wherein the patch as controlled by the controller provides identical boundary conditions for the orthogonal EM modes.

7. The apparatus according to claim 6, wherein the circular patch is configured to provide n-bit phase quantization.

8. The apparatus according to claim 6, wherein the circular patch is configured to provide 2-bit phase quantization.

9. The apparatus according to claim 6, wherein the plurality of switches are PIN diodes.

10. The apparatus according to claim 6, wherein each of the plurality of switches is at least one of a single-pole-single-throw switch and a single-pole-double-throw switch.

11. The apparatus according to claim 6, wherein the signal is circularly polarized.

12. The apparatus according to claim 6, wherein the signal is linearly polarized.

13. An antenna apparatus comprising:

a circular patch having a plurality of orthogonal tap pairs arranged on the patch;

a plurality of switches corresponding to the taps, each of the switches being coupled to ground;

a controller configured to control the switches to short one of the orthogonal tap pairs corresponding to orthogonal EM (electromagnetic) modes; and

a plurality of phase perturbing sources coupled to the taps to apply a fixed phase bias of a predetermined distribution, the predetermined distribution being at least one of a deterministic distribution and a random distribution,

wherein the patch as controlled by the controller provides identical boundary conditions for the orthogonal EM modes.

14. An antenna system for beam steering, comprising:

a plurality of antenna elements being spaced according to a predetermined distance value, each of the plurality of antenna elements comprising,

a circular patch having a plurality of orthogonal tap pairs arranged on the patch,

a plurality of switches corresponding to the taps, each of the switches being coupled to ground, and

a plurality of phase perturbing sources coupled to the taps to apply a fixed phase bias of a predetermined distribution, the predetermined distribution being at least one of a deterministic distribution and a random distribution; and

a controller configured to control individually the plurality of antenna elements, the controller controlling the switches of one of the plurality of antenna elements to short one of the orthogonal tap pairs corresponding to a phase shift of a signal having orthogonal EM (electromagnetic) modes, wherein the circular patch as controlled by the controller provides identical boundary conditions for the orthogonal EM modes.

15. The system according to claim 14, wherein the antenna elements are spaced according to a predetermined value.

16. The system according to claim 15, wherein the predetermined value is 0.5λ

.

17. The system according to claim 14, wherein the number of antenna elements is greater than about 4,000.

18. The system according to claim 14, wherein the circular patch is configured to provide n-bit phase quantization.

19. The system according to claim 14, wherein the circular patch is configured to provide 2-bit phase quantization.

20. The system according to claim 14, wherein the plurality of switches are PIN diodes.

21. The system according to claim 14, wherein each of the plurality of switches is at least one of a single-pole-single-throw switch and a single-pole-double-throw switch.

22. The system according to claim 14, wherein the signal is circularly polarized.

23. The system according to claim 14, wherein the signal is linearly polarized.

24. A computer-readable medium carrying one or more sequences of one or more instructions for performing electronic beam steering using a circular patch having a plurality of taps coupled to a plurality of switches, the one or more sequences of one or more instructions including instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of:

controlling the plurality of switches to short an orthogonal pair of the plurality of taps to provide a phase shift, the taps being arranged on the circular patch to provide identical boundary conditions; and

selectively performing at least one of receiving a signal and transmitting the signal.

25. The computer-readable medium according to claim 24, wherein the signal in the step of selectively performing is circularly polarized.

26. The computer-readable medium according to claim 24, wherein the signal in the step of selectively performing is linearly polarized.

27. The computer-readable medium according to claim 24, wherein the one or more processors further perform the step of:

applying a fixed phase bias of a predetermined distribution to the signal, the predetermined distribution being at least one of a deterministic distribution and a random distribution.