Polarization diverse antenna array arrangement

• US 8,345,716 B1
• Filed: 06/26/2007
• Issued: 01/01/2013
• Est. Priority Date: 06/26/2007
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Ehret, Timothy
• Primary Examiner(s): Thier, Michael
• Assistant Examiner(s): Alia, Curtis A
• Application Number:
  US11/823,146
• Time in Patent Office: 2,016 Days
• Field of Search: 370/310, 370/314, 370/342, 370343-345, 370441-442, 370465-466, 370/498, 370/499, 370/503, 370/507, 370/508, 370/534, 370/535, 370/537, 370/538, 370/540, 370543-544, 370/334, 455/59, 455/101, 455/103, 455/130, 455/132, 455/137, 455/562.1
• US Class Current: 370/537
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

An antenna array includes pairs of antenna elements, each responsive to mutually orthogonal first and second polarizations for producing streams of analog signals. The number of transceivers is halved by time-division multiplexing the analog signals onto a single path and transceiving the stream in that path. The transceived analog signals are digitized, to produce streams of digital samples, alternate ones of which represent the first and second polarizations. Alternate samples of the stream of digitized signals represent the analog received first and second polarizations. Simple processing identifies the polarization of the received signals, and can be used for weather evaluation or for polarimetric identification.

Claims

1. A method for receiving polarized electromagnetic signals at a system, said method comprising the steps of:

transducing a received polarized electromagnetic signal to produce a first stream of analog signals representing a first polarization of said electromagnetic signal and a second stream of analog signals representing a second polarization of said electromagnetic signal which is orthogonal to the first polarization;

multiplexing, by a multiplexer of the system, said first and second streams of analog signals representing said first and second polarizations;

processing said multiplexed first and second streams of analog signals of said first and second polarizations respectively, with a single receiver of the system;

converting said multiplexed, processed analog signals representing said first and second polarizations to digital form with an analog-to-digital and digital-to-analog converter to generate first digital samples representing said first stream of analog signals representing said first polarization and second digital samples representing said second stream of analog signals representing said second polarization; and

processing said first and second digital samples of said first and second streams of analog signals, respectively, to produce first and second digital representations of said first and second streams of analog signals, respectively.

2. The method of claim 1, wherein the step of processing using said single receiver comprises filtering said multiplexed first and second streams of analog signals of said first and second polarizations, respectively.

3. A method for receiving polarized electromagnetic signals at a system, said method comprising the steps of:

transducing a received signal to produce a first stream of analog signals representing a first polarization of said electromagnetic signal and a second stream of analog signals representing a second polarization of said electromagnetic signal which is orthogonal to the first polarization;

multiplexing or interleaving, by a multiplexer of the system, said first and second streams of analog signals representing said first and second polarizations;

processing said multiplexed or interleaved first and second streams of analog signals of said first and second polarizations, respectively, with a single receiver of the system;

converting said multiplexed or interleaved, processed analog signals representing said first and second polarizations to digital form with an analog-to-digital and digital-to-analog converter to generate first digital samples representing said first stream of analog signal signals representing said first polarization and second digital samples representing said second stream of analog signals representing said second polarization; and

processing said first and second digital samples to generate digital signals representing a selected polarization which is different from said first and second polarizations.

4. The method of claim 3, wherein the step of processing using said single receiver comprises amplifying said multiplexed first and second streams of analog signals of said first and second polarizations, respectively.

5. A method for creating arbitrarily polarized versions of an electromagnetic signal at a system, said method comprising the steps of:

transducing said electromagnetic signal with a first antenna element responsive to a first polarization, to generate a first stream of analog signals of said first polarization;

transducing said electromagnetic signal with a second antenna element responsive to a second polarization, to generate a second stream of analog signals of said second polarization;

multiplexing, by a multiplexer of the system, said first and second streams of analog signals of said first and second polarizations, respectively at a multiplexing rate;

downconverting said multiplexed first and second streams of analog signals of said first and second polarizations, respectively, with a single receiver of the system;

converting said multiplexed downconverted first and second streams of analog signals of said first and second polarizations, respectively, to digital form with an analog-to-digital and digital-to-analog converter so that each of said first and second polarizations of said multiplexed first and second streams of analog signals is represented by a digital sample; and

processing said digital samples to create arbitrarily polarized versions of said electromagnetic signal.

6. The method according to claim 5, wherein said step of multiplexing comprises the step of alternately multiplexing to generate alternating analog samples representing said first and second polarizations of said first and second streams of analog signals.

7. The method according to claim 5, wherein said step of converting is performed at said multiplexing rate.

8. The method according to claim 5, wherein said step of processing said digital samples to create said arbitrarily polarized versions of said electromagnetic signal includes the step of complex multiplication.

9. A system for creating arbitrarily polarized versions of an electromagnetic signal, said system comprising:

a first antenna element for generating a first stream of analog signals of a first polarization;

a second antenna element for generating a second stream of analog signals of a second polarization;

a switch for multiplexing said first and second streams of analog signals of said first and second polarizations, respectively at a multiplexing rate;

a single transceiver for downconverting said multiplexed first and second streams of analog signals of said first and second polarizations, respectively;

an analog-to-digital and digital-to-analog converter for converting said downconverted, multiplexed first and second streams of analog signals of said first and second polarizations, respectively, to digital form so that each of said first and second polarizations of said multiplexed first and second streams of analog signals is represented by a digital sample; and

a processor for processing said digital samples to create arbitrarily polarized versions of said electromagnetic signal.

10. The system according to claim 9, wherein said switch generates alternating analog samples representing said first and second streams of analog signals of said first and second polarizations, respectively.

11. The system according to claim 9, wherein said analog-to-digital and digital-to-analog converter converts at said multiplexing rate.

12. The system according to claim 9, wherein said processing performed by said processor includes complex multiplication.

13. The system according to claim 9, wherein the first and second antenna elements are orthogonally-polarized antenna elements.