Super-angular and range-resolution with phased array antenna and multifrequency dither

• US 8,730,095 B1
• Filed: 06/17/2013
• Issued: 05/20/2014
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Volman, Vladimir, Stetson, John B.
• Primary Examiner(s): Sotomayor, John B
• Assistant Examiner(s): WINDRICH, MARCUS E
• Application Number:
  US13/919,634
• Time in Patent Office: 337 Days
• Field of Search: 342/73, 342/74, 342/82, 342/147, 342/157
• US Class Current: 342/153
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured

Abstract

An electromagnetic transmitter arrangement includes an antenna line array or subarray defining at least first and second ends, and including first, second, third, fourth, and fifth antenna elements, arranged with the first antenna element at the first end, the fifth element at the second end, the third element at the center, the second element between the first and third elements, and the fourth element between the third and fifth elements. Multiple (N) corresponding radio frequency sources are provided, each source communicating with a respective antenna element along a given radio-frequency signal path extending from the given signal source to the given antenna element, and where a first signal source generates signals at frequency f0, and each of the N−1 additional sources generate signals at frequencies of f0±(N−1)Δf, where N is an integer greater than or equal to 5.

Claims

1. An electromagnetic transmitter arrangement, comprising:

one of an antenna line array and subarray, said one of said line array and subarray defining at least first and second ends, said one of said line array and subarray including at least first, second, third, fourth, and fifth antenna elements, with said first antenna element at said first end of said one of said line array and subarray, said fifth antenna element at said second end of said one of said line array and subarray, said third antenna element at the center of said one of said line array and subarray, said second antenna element lying between said first and third antenna elements, and said fourth antenna element lying between said third and fifth antenna elements;

first, second, third, fourth, and fifth radio-frequency signal sources each signal source including a dither block to generate signals with a frequency offset that progressively increases at each of said first, second, third, fourth and fifth antenna elements, such that said first signal source generates signals at frequency of f0, said second signal source generates frequencies of f0±

Δ

f, where the symbol ±

means “

plus and minus,”

said third signal source generates frequencies of f0±

2Δ

f, said fourth signal source generates frequencies of f0±

3Δ

f, and said fifth signal source generates frequencies of f0±

4Δ

f; and

a first radio-frequency signal path extending from said first signal source to said first antenna element, a second radio-frequency signal path extending from said second signal source to said second antenna element, a third radio-frequency signal path extending from said third signal source to said third antenna element, a fourth radio-frequency signal path extending from said fourth signal source to said fourth antenna element, and a fifth radio-frequency signal path extending from said fifth signal source to said fifth antenna element, wherein each of said first, second, third, fourth and fifth radio-frequency signal paths includes a controllable switch, each said controllable switch connected in parallel with a corresponding one of said first, second, third, fourth and fifth dither blocks, each said controllable switch configured to bypass the corresponding dither block when the controllable switch is closed.

2. An electromagnetic transmitter arrangement according to claim 1, wherein said one of an antenna line array and subarray is an antenna line array.

3. An electromagnetic transmitter arrangement according to claim 1, wherein said one of an antenna line array and subarray is part of a planar array.

4. An electromagnetic transmitter arrangement according to claim 1, wherein each of said first, second, third, fourth, and fifth radio-frequency signal paths includes one of a phase shifter and a time-delay element.

5. An electromagnetic transmitter arrangement according to claim 1, wherein each of said first, second, third, fourth, and fifth radio-frequency signal paths includes at least one of a phase shifter, an amplifier, and a circulator.

6. An electromagnetic transmitter arrangement according to claim 1, wherein said first, second, third, fourth, and fifth radio-frequency signal sources transmit their respective signals in a synchronized manner.

7. An electromagnetic transmitter arrangement, comprising:

an antenna subarray, comprising first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth antenna elements arranged in first, second, and third rows orthogonally intersecting first, second, and third columns, with said first antenna element lying at the intersection of said first row and said first column, said second antenna element lying at the intersection of said first row and said second column, said third antenna element lying at the intersection of said first row and said third column, said fourth antenna element lying at the intersection of said second row and said first column, said fifth antenna element lying at the intersection of said second row and said second column, said sixth antenna element lying at the intersection of said second row and said third column, said seventh antenna element lying at the intersection of said third row and said first column, said eighth antenna element lying at the intersection of said third row and said second column, and said ninth antenna element lying at the intersection of said third row and said third column;

first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth radio-frequency signal sources, said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth signal sources generating radio-frequency signals at frequencies f0±

8Δ

f+f0 at double amplitude, f0±

7Δ

f+f0 at double amplitude, f0±

6Δ

f+f0 at double amplitude, f0±

8Δ

f±

δ

f, f0±

7Δ

f±

δ

f, f0±

6Δ

f±

δ

f, f0±

8Δ

f±

2δ

f, f0±

7Δ

f±

2δ

f, f0±

6Δ

f±

2δ

f, respectively; and

first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth coupling elements interconnecting said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth antenna elements with said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth radio-frequency signal sources, respectively.

8. An electromagnetic transmitter arrangement according to claim 7, wherein said antenna subarray is part of a planar array.

9. An electromagnetic transmitter arrangement according to claim 7, wherein said coupling elements include one of a phase shifter element and a time delay element.

10. An electromagnetic transmitter arrangement according to claim 7, wherein each of said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth coupling elements includes at least one of a phase shifter, an amplifier, and a circulator.

11. An electromagnetic transmitter arrangement according to claim 7, wherein said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth radio-frequency signal sources transmit their respective signals in a synchronized manner.

12. An electromagnetic transmitter arrangement comprising:

an antenna subarray, comprising first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth antenna elements arranged in first, second, and third rows orthogonally intersecting first, second, and third columns, with said first antenna element lying at the intersection of said first row and said first column, said second antenna element lying at the intersection of said first row and said second column, said third antenna element lying at the intersection of said first row and said third column, said fourth antenna element lying at the intersection of said second row and said first column, said fifth antenna element lying at the intersection of said second row and said second column, said sixth antenna element lying at the intersection of said second row and said third column, said seventh antenna element lying at the intersection of said third row and said first column, said eighth antenna element lying at the intersection of said third row and said second column, and said ninth antenna element lying at the intersection of said third row and said third column;

first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth radio-frequency signal sources, said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth signal sources generating radio-frequency signals at a carrier frequency, where said carrier frequency changes from element to element to define a first bidirectional frequency gradient in the column direction of said array and to define a second bidirectional frequency gradient in the row directions of said array.

13. An electromagnetic transmitter arrangement according to claim 12, wherein said first and second bidirectional frequency gradients are mutually different.

14. An electromagnetic transmitter arrangement according to claim 12, wherein said first bidirectional frequency gradient is a stepwise frequency gradient Δ

f and said second bidirectional frequency gradient is a stepwise bidirectional frequency gradient δ

f.

15. An electromagnetic transmitter arrangement according to claim 12, further comprising first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth signal paths interconnecting said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth antenna elements with said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth radio-frequency signal sources, respectively.

16. An electromagnetic transmitter arrangement according to claim 15, wherein each of said first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth signal paths includes at least one of a phase shifter, a time delay element, an amplifier, and a circulator.

17. An electromagnetic transmitter arrangement comprising:

one of an antenna line array and subarray, said one of said line array and subarray defining at least first and second ends, said one of said line array and subarray including at least first, second, third, fourth, and fifth antenna elements, with said first antenna element at said first end of said one of said line array and subarray, said fifth antenna element at said second end of said one of said line array and subarray, said third antenna element at the center of said one of said line array and subarray, said second antenna element lying between said first and third antenna elements, and said fourth antenna element lying between said third and fifth antenna elements;

first, second, third, fourth, and fifth radio-frequency signal sources, said first signal source generating signals at frequency of f0, said second signal source generating frequencies of f0±

Δ

f, where the symbol ±

means “

plus and minus,”

said third signal source generating frequencies of f0±

2Δ

f, said fourth signal source generating frequencies of f0±

3Δ

f, and said fifth signal source generating frequencies of f0±

4Δ

f, wherein signal sources having a positive frequency offset generate a counter-clockwise rotating beam, and signal sources having a negative frequency offset generate a clockwise rotating beam; and

a first radio-frequency signal path extending from said first signal source to said first antenna element, a second radio-frequency signal path extending from said second signal source to said second antenna element, a third radio-frequency signal path extending from said third signal source to said third antenna element, a fourth radio-frequency signal path extending from said fourth signal source to said fourth antenna element, and a fifth radio-frequency signal path extending from said fifth signal source to said fifth antenna element.

18. An electromagnetic transmitter arrangement according to claim 17, wherein said one of an antenna line array and subarray is part of a planar array.

19. An electromagnetic transmitter arrangement according to claim 17, wherein each of said first, second, third, fourth, and fifth radio-frequency signal paths includes one of a phase shifter and a time-delay element.

20. An electromagnetic transmitter arrangement according to claim 17, wherein said first, second, third, fourth, and fifth radio-frequency signal sources transmit their respective signals in a synchronized manner.