Multi-aperture three-dimensional beamforming

• US 8,559,823 B2
• Filed: 06/06/2008
• Issued: 10/15/2013
• Est. Priority Date: 06/06/2007
• Status: Active Grant

• Current Assignee: TiaLinx, Inc.
• Original Assignee: TiaLinx, Inc.
• Inventors: Izadpanah, Hossein, Mohktari, Mehran
• Primary Examiner(s): Vanderpuye, Kenneth N
• Assistant Examiner(s): Wolf, Darren E
• Application Number:
  US12/135,138
• Publication Number:
  US 20090092158A1
• Time in Patent Office: 1,957 Days
• Field of Search: None
• US Class Current: 398/115
• CPC Class Codes: G01S 13/24 using frequency agility of carrier wave
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: H01Q 3/2676 Optically controlled phased array

Abstract

In one embodiment, a system is provided that includes: a mode-locked laser source configured to provide a pulsed multi-frequency laser output signal having spectrum with a plurality of comb lines, wherein one of the comb lines is a reference comb line, the comb lines forming a plurality of comb line pairs comprising the reference comb line and selected ones of the remaining comb lines; a plurality of optical-electronic (OE) conversion circuits, each OE circuit corresponding on a one-to-one basis to the plurality of comb line pairs, wherein each OE circuit is configured to provide an electrical output signal having a frequency corresponding to a heterodyning of the comb lines in its corresponding comb line pair; a plurality of amplifiers corresponding on a one-to-one basis with the OE conversion circuits, each amplifier configured to amplify a version of the electrical output signal from its corresponding OE conversion circuit so as to provide an amplified output signal; and an array of antennas corresponding on a one-to-one basis to the plurality of amplifiers, each antenna configured to transmit the amplified output signal from the corresponding amplifier, whereby the array of antennas transmits a coherent and multi-frequency signal output pulse.

Claims

1. A system, comprising:

a mode-locked laser source configured to provide a pulsed multi-frequency laser output signal having a spectrum with a plurality of comb lines, wherein one of the comb lines is a reference comb line, the comb lines forming a plurality of comb line pairs comprising the reference comb line and selected ones of the remaining comb lines;

a plurality of N optical-electronic (OE) conversion circuits, each OE circuit corresponding on a one-to-one basis to the plurality of comb line pairs, wherein each OE circuit is configured to provide an electrical output signal having a frequency corresponding to a heterodyning of the comb lines in its corresponding comb line pair, and wherein the frequency for a first one of OE conversion circuits equals a pulse repetition frequency multiple (PRF) for the comb lines;

a frequency for a second one of the OE conversion circuits equals 2*PRF, and so on such that a final Nth one of the OE conversion circuits has a frequency of N*PRF;

a plurality of amplifiers corresponding on a one-to-one basis with the OE conversion circuits, each amplifier configured to amplify a version of the electrical output signal from its corresponding OE conversion circuit so as to provide an amplified output signal;

an array of antennas corresponding to the plurality of amplifiers, each antenna configured to transmit the amplified output signal from the corresponding amplifier, whereby the array of antennas transmits a coherent and multi-frequency signal output pulse;

a plurality of variable phase-shifters corresponding on a one-to-one basis with the OE conversion circuits, each variable phase-shifter configured to phase-shift the version of the electrical output signal provided to the amplifier corresponding to the phase-shifter'"'"'s OE conversion circuit; and

a controller configured to control the variable phase-shifters such that the multi-frequencies in the output pulse constructively add with each other at a desired range, azimuth, and elevation angle with respect to the array.

2. The system of claim 1, wherein each antenna comprises a sub-array of antennas.

3. The system of claim 1, wherein the array of antennas is a linear array.

4. The system of claim 1, wherein the array of antennas is a circular array.

5. The system of claim 1, wherein the array of antennas is a hemispherical array.

6. A method of producing a coherent and multi-frequency output signal pulse, comprising:

generating a coherent optical comb signal, the optical comb signal including a reference comb line and a plurality of remaining comb lines, the reference comb line corresponding to the plurality of remaining comb lines so as to form unique comb line pairs, the coherent optical comb signal being pulsed at a pulse repetition frequency multiple (PRF);

heterodyning the comb line pairs to produce N electrical comb lines signals separated in frequency by the PRF such that the electrical comb lines range in frequency from PRF to N*PRF;

transmitting versions of the electrical comb lines signals through antennas to form the coherent and multi-frequency output signal pulse; and

controlling a phase of each of the electrical comb line signals relative to each other so that the multi-frequency output signals constructively add together at a desired range, elevation angle, and azimuth angle with respect to the array.