System and method for pattern design in microwave programmable arrays

• US 8,289,199 B2
• Filed: 03/24/2005
• Issued: 10/16/2012
• Est. Priority Date: 03/24/2005
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Baharav, Izhak, Taber, Robert C., Lee, Gregory S.
• Primary Examiner(s): Chen, Shelley
• Application Number:
  US11/089,298
• Publication Number:
  US 20060214836A1
• Time in Patent Office: 2,763 Days
• Field of Search: 342/176, 342/179, 342/180, 342170-174, 342146-149, 342153-158, 342/368, 342371-374
• US Class Current: 342/6
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays

Abstract

An antenna array for use within a microwave imaging system to capture a microwave image of a target is selectively programmed to optimize one or more parameters of the microwave imaging system. The array includes a plurality of antenna elements, each capable of being programmable with a respective phase shift to direct a beam of microwave radiation toward the target such that the microwave radiation from each of the plurality of antenna elements arrives at the target substantially in-phase. To optimize a parameter of the microwave imaging system, the phase shifts of selective ones of the antenna elements are altered, while still maintaining the substantially in-phase microwave radiation at the target.

Claims

1. An array for use in a microwave imaging system to capture a microwave image of a target, comprising:

a plurality of antenna elements, each capable of being programmable with a respective phase shift to direct a beam of microwave radiation toward the target such that the microwave radiation from each of the plurality of antenna elements arrives at the target substantially in-phase;

wherein the phase shifts of selective ones of the plurality of antenna elements are altered to optimize a minimum number of phase shift changes in the array between successive microwave images.

2. The array of claim 1, wherein each of said plurality of antenna elements are discrete phase-shifted antenna elements.

3. The array of claim 1, wherein each of said plurality of antenna elements is a reflecting antenna element, and wherein each said reflecting antenna element is configured to receive microwave illumination from a microwave source and reflect the microwave illumination based on the respective programmed phase shift to direct the beam of microwave radiation toward the target.

4. The array of claim 3, wherein each said reflecting antenna element is configured to receive a reflected beam of microwave radiation reflected from the target and reflect the reflected beam towards a microwave receiver based on the respective programmed phase shift associated with each said reflecting antenna element.

5. The array of claim 4, wherein the parameter to be optimized is a ratio of constructive interference of the microwave radiation at the target and destructive interference of the microwave radiation at the microwave receiver.

6. The array of claim 5, wherein the ratio is optimized by increasing the destructive interference at the microwave receiver without a corresponding decrease in the constructive interference at the target.

7. The array of claim 5, wherein the phase shifts of each of the plurality of antenna elements are chosen based on an ideal phase, and wherein each of the selective antenna elements produces a respective beam of microwave radiation having a phase offset from the ideal phase greater than other ones of the plurality of antenna elements.

8. The array of claim 1, wherein the array is designed for use in scanning an object by capturing successive microwave images of targets associated with the object, and wherein the minimum number of phase shift changes is optimized by selecting an order for the successive microwave images.

9. The array of claim 1, wherein the parameter to be optimized is a ratio of a main lobe area to side lobe areas.

10. The array of claim 1, wherein the phase shifts programmed for each of the plurality of antenna elements to direct the beam of microwave radiation to the target form a pattern, and wherein the parameter to be optimized is a metric associated with digital compression of bits describing the pattern.

11. A microwave imaging system for capturing a microwave image of a target, comprising:

a microwave source for providing microwave radiation for illuminating the target; and

a reflector antenna array including a plurality of antenna elements, each of said antenna elements being capable of being programmed with a respective phase shift to reflect the microwave radiation towards the target in a transmit beam such that the microwave radiation from each of the plurality of antenna elements arrives at the target substantially in-phase;

wherein the phase shift of selective ones of the plurality of antenna elements is altered to optimize a minimum number of phase shift chances in the array between successive microwave images.

12. The system of claim 11, wherein the antenna elements are further capable of receiving reflected microwave illumination reflected from the target in a receive beam and reflecting the receive beam towards a microwave receiver.

13. The system of claim 12, wherein the parameter to be optimized is a ratio of constructive interference of the microwave radiation at the target and destructive interference of the microwave radiation at a microwave receiver.

14. The system of claim 13, wherein the ratio is optimized by increasing the destructive interference at the microwave receiver without a corresponding decrease in the constructive interference at the target.

15. The system of claim 13, wherein the phase shifts of each of the plurality of antenna elements are chosen based on an ideal phase, and wherein each of the selective antenna elements produces a respective beam of microwave radiation having a phase offset from the ideal phase greater than other ones of the plurality of antenna elements.

16. The system of claim 11, wherein the array is designed for use in scanning an object by capturing successive microwave images of targets associated with the object, and wherein the minimum number of phase shift changes is optimized by selecting an order for the successive microwave images.

17. The system of claim 11, wherein the parameter to be optimized is a ratio of a main lobe area to side lobe areas.

18. The system of claim 11, wherein the phase shifts programmed for each of the plurality of antenna elements to direct the beam of microwave radiation to the target form a pattern, and wherein the parameter to be optimized is a metric associated with digital compression of bits describing the pattern.

19. A method for optimizing operation of a microwave imaging system for capturing a microwave image of a target, comprising:

providing an array including a plurality of programmable microwave antenna elements;

designing a pattern of respective phase shifts for each of the microwave antenna elements to direct a transmit beam of microwave radiation towards the target; and

altering the phase shift of selective ones of the plurality of antenna elements in the pattern to optimize a minimum number of phase shift changes in the array between successive microwave images; and

applying the altered phase shifts to the array.

20. The method of claim 19, wherein the parameter to be optimized is a ratio of constructive interference of the microwave radiation at the target and destructive interference of the microwave radiation at a microwave receiver.

21. The method of claim 20, wherein the altering further includes increasing the destructive interference at the microwave receiver without a corresponding decrease in the constructive interference at the target.

22. The method of claim 20, wherein the designing further includes selecting the phase shills of each of the plurality of antenna elements based on an ideal phase, and wherein the altering further includes altering the phase shift of the selective antenna elements that produce a respective beam of microwave radiation having a phase offset from the ideal phase greater than other ones of the plurality of antenna elements.

23. The method of claim 19, wherein the altering further includes selecting an order for the successive microwave images to optimize the minimum number of phase shift changes therebetween.

24. The method of claim 19, wherein the parameter to be optimized is a ratio of a main lobe area to side lobe areas.

25. The method of claim 19, wherein the parameter to be optimized is a metric associated with digital compression of bits describing the pattern.