System and method for microwave imaging using an interleaved pattern in a programmable reflector array

• US 20060214833A1
• Filed: 03/24/2005
• Published: 09/28/2006
• 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.
• Granted Patent: US 7,333,055 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• 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 includes a plurality of reflecting antenna elements, each capable of being programmed with respective phase-shifts in a first pattern to direct a first beam of microwave radiation towards a first target, and each being capable of being programmed with respective phase-shifts in a second pattern to direct a second beam of microwave radiation towards a second target. To capture a microwave image of an object, the antenna elements are programmed with respective phase-shifts in an interleaved pattern including a portion of the first pattern and a portion of the second pattern.

Claims

1. A reflector array for use in a microwave imaging system to capture a microwave image of an object, comprising:

a plurality of reflecting antenna elements, each capable of being programmed with respective phase-shifts in a first pattern to direct a first beam of microwave radiation towards a first target, and each being capable of being programmed with respective phase-shifts in a second pattern to direct a second beam of microwave radiation towards a second target;

wherein said plurality of antenna elements are programmed with respective phase-shifts in an interleaved pattern including a portion of said first pattern and a portion of said second pattern to capture said microwave image of said object.

2. The array of claim 1, wherein said interleaved pattern is a direct interleaved pattern of said first pattern and said second pattern.

3. The array of claim 1, wherein said first target is associated with said object being imaged and said second target is associated with said object.

4. The array of claim 1, wherein said first target is a target associated with said object being imaged and said second target is a microwave receiver, and wherein said first pattern is a transmit pattern for directing said first beam of microwave radiation towards said target as a transmit beam and said second pattern is a receive pattern for reflecting said second beam of microwave radiation reflected from said target object towards said microwave receiver as a receive beam, said microwave image being a microwave image of said target.

5. The array of claim 4, wherein said portion of said transmit pattern and said portion of said receive pattern in said interleaved pattern are each selected to increase the destructive interference at said microwave receiver without a corresponding decrease in the constructive interference at said target of said object.

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

7. The array of claim 6, wherein said phase-shifts of each of said plurality of antenna elements for said first pattern and said second pattern are selected based on an ideal phase, and wherein said portion of said first pattern and said portion of said second pattern in said interleaved pattern are each selected to minimize a quantization error based on a phase offset from said ideal phase for each of said plurality of antenna elements.

8. The array of claim 6, wherein said portion of said first pattern and said portion of said second pattern in said interleaved pattern are each selected to minimize a number of phase-shift changes in said array between successive microwave images.

9. The array of claim 6, wherein said quantized phase-shifted antenna elements are binary phase-shifted antenna elements.

10. The array of claim 1, wherein said portion of said first pattern and said portion of said second pattern included in said interleaved pattern are each selected to optimize a metric associated with the digital compression of said interleaved pattern.

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

a microwave source for providing microwave radiation;

a microwave receiver for receiving microwave radiation; and

a reflector antenna array including a plurality of antenna elements, each of said antenna elements being capable of being programmed with respective phase-shifts in a transmit pattern to direct a beam of microwave radiation from said microwave source towards said target, and each being capable of being programmed with respective phase-shifts in a receive pattern to reflect a reflected beam of microwave radiation reflected from said target towards said microwave receiver;

wherein said plurality of antenna elements are programmed with respective phase-shifts in an interleaved pattern including a portion of said transmit pattern and a portion of said receive pattern to capture said microwave image of said target.

12. The system of claim 11, wherein said interleaved pattern is a direct interleaved pattern of said transmit pattern and said receive pattern.

13. The system of claim 11, wherein said portion of said transmit pattern and said portion of said receive pattern in said interleaved pattern are each selected to increase the destructive interference at said microwave receiver without a corresponding decrease in the constructive interference at said target.

14. The system of claim 11, wherein each of said plurality of antenna elements are quantized phase-shifted antenna elements.

15. The system of claim 14, wherein said phase-shifts of each of said plurality of antenna elements for said transmit pattern and said receive pattern are selected based on an ideal phase, and wherein said portion of said transmit pattern and said portion of said receive pattern in said interleaved pattern are each selected to minimize a quantization error based on a phase offset from said ideal phase for each of said plurality of antenna elements.

16. The system of claim 14, wherein said portion of said transmit pattern and said portion of said receive pattern in said interleaved pattern are each selected to minimize a number of phase-shift changes in said array between successive microwave images.

17. A method for capturing a microwave image of a target, comprising:

providing an array including a plurality of reflecting antenna elements;

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

designing a receive pattern of respective phase-shifts for each of the reflecting antenna elements to reflect a reflected beam of microwave radiation reflected from the target towards a microwave receiver; and

programming each of the microwave antenna elements with a respective phase-shift in an interleaved pattern including a portion of the transmit pattern and a portion of the receive pattern.

18. The method of claim 17, wherein said interleaved pattern is a direct interleaved pattern of said transmit pattern and said receive pattern.

19. The method of claim 17, wherein said programming includes selecting the portion of the transmit pattern and the portion of the receive pattern in said interleaved pattern to increase the destructive interference at the microwave receiver without a corresponding decrease in the constructive interference at the target.

20. The method of claim 17, wherein said designing the transmit pattern and said designing the receive pattern includes selecting the phase-shifts of each of the plurality of antenna elements for the transmit pattern and the receive pattern based on an ideal phase.

21. The method of claim 20, wherein each of the reflecting antenna elements are quantized phase-shifted antenna elements, and wherein said programming further includes selecting the portion of the transmit pattern and the portion of the receive pattern in the interleaved pattern to minimize a quantization error based on a phase offset from the ideal phase for each of the plurality of antenna elements.

22. The method of claim 20, wherein said programming further includes selecting the portion of the transmit pattern and the portion of the receive pattern in the interleaved pattern to minimize a number of phase-shift changes in the array between successive microwave images.