Frequency selective leveling loop for multi-signal phased array transmitters

• US 20060068707A1
• Filed: 09/24/2004
• Published: 03/30/2006
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: CAES Systems LLC
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Greeley, John S.
• Granted Patent: US 7,668,509 B2
• Time in Patent Office: Days
• US Class Current: 455/42
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/084 Equal gain combining, only phase adjustments antenna beam scanning or forming by phase or amplitude control H01Q3/26, e.g. phased arrays
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115

Abstract

A frequency selective leveling loop that performs phase and amplitude control of multiple signals within a phased array structure is disclosed. The leveling loop sensor componants are embedded into the array structure. The frequency selective leveling loop can be used with multiple signal amplifiers, and a conventional phase array jamming system can be used to radiate multiple signals simultaneously. The conversion of phase information to baseband eliminates the need for phase matched cables. The frequency selective leveling that is enabled is tolerant of multiple signals and provides the individual signal phase and amplitude feedback by utilizing analytic sampling.

Claims

1. A frequency selective leveling loop device for multi-signal phased array transmitters, comprising:

a multi-signal exciter adapted to process a plurality of exciter signals and to sum the exciter signals, thereby forming a composite signal;

an I and Q down converter adapted to convert a sample of the composite signal to I and Q signals, by mixing the composite signal with an amplitude limited exciter signal sample, thereby providing two mixed outputs that each include a number of AC signals and a DC component; and

a digital low pass filter adapted to remove the AC signals from the mixed outputs leaving only the DC component, thereby enabling at least one of amplitude leveling and steering of each signal in an independent beam.

2. The device of claim 1 further comprising an RF power amplifier adapted to amplify the composite signal.

3. The device of claim 2 further comprising a sampling coupler adapted to provide the amplified composite signal to an antenna element for transmission, and to provide the sample of the composite signal.

4. The device of claim 3 wherein the RF power amplifier and the sampling coupler are configured to provide an overall unity gain.

5. The device of claim 1 further comprising an I and Q to signal amplitude and phase angle converter adapted to convert the DC component to amplitude and phase angle of the composite signal sample.

6. The device of claim 1 further comprising a time multiplexed signal sample and amplitude limiter adapted to sequentially sample exciter signals, thereby providing the amplitude limited exciter signal sample.

7. The device of claim 1 wherein the device is implemented as one of an integrated circuit chip or chip set.

8. The device of claim 1 wherein the low pass filter is variable in bandwidth to accommodate a plurality of signal situations.

9. A frequency selective leveling loop device for multi-signal phased array transmitters, comprising:

a multi-port exciter adapted to process a plurality of exciter signals and to sum the exciter signals, thereby forming a composite signal;

an RF power amplifier adapted to amplify the composite signal;

a sampling coupler adapted to provide the amplified composite signal to an antenna element of the phased array for transmission, and to provide the sample of the composite signal;

a time multiplexed signal sample and amplitude limiter module adapted to sequentially sample exciter signals, thereby providing an amplitude limited exciter signal sample;

an I and Q down converter adapted to convert the sample of the composite signal to I and Q signals, by mixing the composite signal with the amplitude limited exciter signal sample, thereby providing two mixed outputs that each include a number of AC signals and a DC component;

a digital low pass filter adapted to remove the AC signals from the mixed outputs leaving only the DC component; and

an I and Q to signal amplitude and phase angle converter adapted to convert the DC component to amplitude and phase angle of the composite signal sample, thereby enabling at least one of amplitude leveling and steering of each signal in an independent beam.

10. The device of claim 9 wherein the RF power amplifier and the sampling coupler are configured to provide an overall unity gain.

11. The device of claim 9 wherein the device is implemented as one of an integrated circuit chip or chip set.

12. The device of claim 9 wherein the low pass filter is variable in bandwidth to accommodate a plurality of signal situations.

13. An I/Q phase and amplitude sensor for a frequency selective leveling loop for multi-signal phased array transmitters, the sensor comprising:

an I and Q down converter adapted to convert a sample of a composite signal including a number of exciter signals to I and Q signals, by mixing the composite signal with an amplitude limited exciter signal sample, thereby providing two mixed outputs that each include a number of AC signals and a DC component.

14. The sensor of claim 13 wherein the composite signal is provided by a multi-signal exciter adapted to process a plurality of exciter signals and to sum the exciter signals, thereby forming the composite signal.

15. The sensor of claim 14 wherein the composite signal is amplified and provided to an antenna element for transmission.

16. The sensor of claim 13 further comprising a digital low pass filter adapted to remove the AC signals from the mixed outputs leaving only the DC component, thereby enabling at least one of amplitude leveling and steering of each signal in an independent beam.

17. The sensor of claim 16 wherein the low pass filter is variable in bandwidth to accommodate a plurality of signal situations.

18. The sensor of claim 13 further comprising an I and Q to signal amplitude and phase angle converter adapted to convert the DC component to amplitude and phase angle of the composite signal sample.

19. The sensor of claim 13 further comprising a time multiplexed signal sample and amplitude limiter adapted to sequentially sample exciter signals, thereby providing the amplitude limited exciter signal sample.

20. The sensor of claim 13 wherein the sensor is implemented as one of an integrated circuit chip or chip set.