Real time polarization compensation for dual-polarized millimeter wave communication

Patent metadata

Field	Value
Publication number	US-10063264-B2
Application number	US-201615164959-A
Country	US
Kind code	B2
Filing date	May 26, 2016
Priority date	Jul 28, 2015
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A communication system comprises a signal generator, polarizer, signal combiner, transmitter, positioning device, and controller. The signal generator converts first and second received data streams into respective first and second orthogonal linearly polarized signals. The polarizer is at a first rotation angle and converts first and second orthogonal linearly polarized signals into, respectively, a first right-hand-circularly polarized (RHCP) signal and first left-hand circularly polarized (LHCP) signal, which are combined in signal combiner into a signal sent by transmitter to a receiver. The positioning device adjusts the first rotation angle to substantially increase isolation between third and fourth orthogonal linearly polarized signals at the receiver. The controller performs the real-time analysis of transmission loss and directs the positioning device to adjust the first rotation angle.

First claim

What is claimed is:

1. A method for transmitting signals from a first communication node to a second communication node, the method comprising:
receiving first and second data streams to be transmitted from the first communication node;
converting the first and second data streams to first and second orthogonal linearly polarized signals;
receiving the first and second orthogonal linearly polarized signals at a first polarizer, the first polarizer oriented at a first rotation angle, wherein the first polarizer converts the first and second orthogonal linearly polarized signals to, respectively, a first right-hand-circularly polarized (RHCP) signal and a first left-hand circularly polarized (LHCP) signal;
combining the first RHCP signal and first LHCP signal into a transmitted signal having a first signal strength and providing the transmitted signal transmitted to a receiver; and
adjusting the first rotation angle to substantially increase isolation between third and fourth orthogonal linearly polarized signals at the receiver, the adjusting comprising dynamically adjusting the first rotation angle in accordance with a redetermined periodic rotation angle update rate, wherein the third and fourth orthogonally linearized polarize signals are derived, respectively, from the transmitted signal received at the receiver, and correspond, respectively to transmitted versions of the first and second linearly polarized signals, wherein the adjusting is based at least in part on a real-time analysis of a transmission loss of the of the third and fourth orthogonal linearly polarized signals as compared to the transmitted signal as sent by the transmitter.

2. The method of claim 1 , wherein the adjustment of the first rotation angle is further based at least in part on information relating to the second rotation angle of a second polarizer configured to receive the transmitted signal.

3. The method of claim 2 , further comprising providing information usable to adjust the second rotation angle to substantially increase isolation between the third and fourth orthogonal linearly polarized signals at the receiver, wherein the adjusting is based at least in part on the real-time analysis of the transmission loss of the of the third and fourth orthogonal linearly polarized signals as compared to the transmitted signal as sent by the transmitter.

4. The method of claim 2 , further comprising adjusting the first rotation angle based at least in part on computation of a misalignment angle between the first and second rotation angles.

5. The method of claim 4 , wherein the computation provides an estimation of the misalignment angle.

6. The method of claim 4 , wherein determining the misalignment angle is based at least in part on a real-time measurement of at least one of the first and second rotation angles.

7. The method of claim 6 , wherein determining the misalignment angle is based at least in part on at least one property of at least one of the first and second polarizers.

8. The method of claim 7 , further comprising;
computing at least one operating point based at least in part on at least one of the first rotation angle, second rotation angle, and at least one property of at least one of the first and second wave plates, wherein the at least one operating point corresponds to a transmitter and receiver rotational angle arrangement configured to achieve at least a predetermined level of isolation between the third and fourth orthogonal linearly polarized signals.

9. The method of claim 8 wherein the at least one operating point corresponds to a transmitter and receiver polarizer rotational angle arrangement that is configured to substantially maximize the level of isolation between the third and fourth orthogonal linearly polarized signals.

10. The method of claim 1 , wherein at least one of the first and second communication nodes is in motion relative to the other of the first and second communication nodes.

11. The method of claim 1 , wherein the first and second orthogonal linearly polarized signals are oriented so as to be parallel to the orthogonal axes of the first quarter wave plate.

12. The method of claim 2 , wherein the second and third orthogonal linearly polarized signals are oriented to be substantially parallel to rotated polarization axes of the second quarter wave plate.

13. The method of claim 2 , further comprising;
measuring at least one of the first and second rotation angles;
calibrating a phase between the first and second orthogonal linearly polarized signals;
computing, based at least in part on least one of a property of at least one of the first and second polarizers and on measurement of at least one of the first and second rotation angles, a misalignment angle between the first and second polarizers;
determining, based at least in part on least one of the property of at least one of the first and second polarizers, on the measurement of at least one of the first and second rotation angles, and on the misalignment angle, a correction angle and phase shift error associated with at least one of the first and second polarizers; and
rotating at least one of the first and second polarizers to a respective first or second rotation angle selected in accordance with the correction angle and phase shift error, wherein the rotating is configured to substantially compensate for at least one of the misalignment angle and phase shift error between the first and second polarizers.

14. A communication system, comprising:
a signal generator configured to convert first and second received data streams into respective first and second orthogonal linearly polarized signals;
a first polarizer oriented at a first rotation angle and configured to be in operable communication with the signal generator, the first polarizer further configured to convert the first and second orthogonal linearly polarized signals to respective first and second orthogonal linearly polarized signals wherein the first polarizer converts the first and second orthogonal linearly polarized signals to, respectively, a first right-hand-circularly polarized (RHCP) signal and a first left-hand circularly polarized (LHCP) signal;
a signal combiner in operable communication with the first polarizer, the signal combiner configured to combine the first RHCP signal and first LHCP signal into a transmitted signal having a first signal strength;
a transmitter in operable communication with the signal combiner, the transmitter configured to provide the transmitted signal to a receiver,
a positioning device in operable communication with the polarizer, the positioning device configured to adjust the first rotation angle to substantially increase isolation between third and fourth orthogonal linearly polarized signals at the receiver, wherein the adjusting is based at least in part on a real-time analysis of a transmission loss of the of the third and fourth orthogonal linearly polarized signals, wherein the third and fourth orthogonally linearized polarize signals are derived, respectively, from the transmitted signal received at the receiver, and correspond, respectively to transmitted versions of the first and second linearly polarized signals; and
a controller in operable communication with the positioning device, the controller configured to perform the real-time analysis, to direct the positioning device to adjust the first rotation angle, and to dynamically adjust the first rotation angle in accordance with a predetermined periodic rotation angle update rate.

15. The communication system of claim 14 , wherein the adjustment of the first rotation ang

Assignees

• Raytheon Co

Inventors

• Crouch David D
• Brown Kenneth W

Classifications

• H01Q15/244 Primary

  converting a linear polarised wave into a circular polarised wave (guided wave H01P1/17) · CPC title

• H04B1/0475 Primary

  with means for limiting noise, interference or distortion (H04B1/0483 takes precedence) · CPC title

• H04L27/04

  Modulator circuits; Transmitter circuits · CPC title

• H01Q15/246

  rotating the plane of polarisation of a linear polarised wave (guided wave H01P1/165) · CPC title

• H01Q13/0258

  Orthomode horns (orthomode transducers H01P1/161) · CPC title