Tracking system with orthogonal polarizations and a retro-directive array

• US 9,306,647 B2
• Filed: 04/27/2015
• Issued: 04/05/2016
• Est. Priority Date: 03/01/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Lattice Semiconductor Corporation
• Inventors: Aryanfar, Farshid
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US14/697,424
• Publication Number:
  US 20150244441A1
• Time in Patent Office: 344 Days
• Field of Search: 455/78
• US Class Current: 1/1
• CPC Class Codes: H01Q 3/2647 Retrodirective arrays
• CPC Class Codes: H03F 2200/198 A hybrid coupler being used as coupling circuit between stages of an amplifier circuit
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits

Abstract

The disclosed embodiments relate to a retro-directive array that facilitates a tracking operation. This retro-directive array includes a first antenna configured to receive an input signal which is substantially circularly polarized from a tracking device. The first antenna separates the input signal into two signal components (e.g., E_x and E_y) associated with different orthogonal polarizations, wherein the two signal components comprise a quadrature signal wherein E_y=j·Ex. The retro-directive array also includes a bi-directional quadrature gain (BQG) module coupled to the first antenna which is configured to boost the quadrature signal. It additionally includes a second antenna which configured to transmit the boosted quadrature signal to the tracking device. The disclosed embodiments also relate to a transceiver switch, which includes: an input configured to receive a signal to be transmitted, and two phase mixers configured to receive the signal to be transmitted and phase inputs I and Q, and to produce a signal comprising two quadrature signal components S_I and S_Q, respectively, wherein S_Q=j S_I. The transmit switch also includes a hybrid coupler, which is configured to combine S_I phase shifted by 180° with S_Q phase shifted by 90° to produce a transmit output which is proportionate to S; and a switching mechanism configured to turn off the transmit output by swapping the phase inputs I and Q to the phase mixers.

Claims

1. A transmit switch, comprising:

two phase mixers configured to receive a signal to be transmitted and phase inputs I and Q, and to produce a quadrature signal comprising two signal components S_Q and S_I;

a hybrid coupler, wherein the hybrid coupler is to combine S_Q phase shifted by 90°

with S_I phase shifted by 180°

to produce a transmit output; and

a switching mechanism to turn off the transmit output by, swapping the phase inputs I and Q at the phase mixers, and

combining S_Q phase shifted by 180°

with S_I phase shifted by 90°

to produce a null transmit output.

2. The transmit switch of claim 1, further comprising an antenna to transmit the transmit signal toward a target device.

3. The transmit switch of claim 2,

wherein the transmit signal is transmitted through the antenna with a first polarization;

wherein the target device includes a retro-directive array which receives the transmitted signal and generates a return signal with a second polarization that is orthogonal to the first polarization; and

wherein the antenna is configured to receive the return signal.

4. The transmit switch of claim 3, wherein the retro-directive array comprises:

a first dual-polarized antenna with a first element and a second element, which are associated with different polarizations; and

a second dual-polarized antenna with a first element and a second element, which are associated with different polarizations;

wherein a first signal received through the first element of the first dual-polarized antenna feeds through a gain element G₁ and a delay element D₁, and is returned through the second element of the second dual-polarized antenna; and

wherein a second signal received through the first element of the second dual-polarized antenna feeds through a gain element G₂ and a delay element D₂, and is returned through the second element of the first dual-polarized antenna.

5. The transmit switch of claim 2,

wherein the antenna is shared between a transmitter and a receiver, wherein the target device includes a retro-directive array which receives the transmitted signal and generates a return signal, wherein the transmit switch further comprises a receive switch;

wherein during a transmit cycle the receive switch is turned off by,

receiving an input from the antenna and feeding the input through two phase mixers with phase inputs Q and I to produce quadrature signals R_Q and R_I; and

combining R_Q phase shifted by 180°

with R_I phase shifted by 90°

to produce a null receive input; and

wherein after the transmit cycle, the receive switch is turned on by, swapping the phase inputs Q and I of the two phase mixers, and

combining R_I phase shifted by 180°

with R_Q phase shifted by 90°

to receive the return signal.

6. The transmit switch of claim 5, wherein the transmit switch and the receive

switch are configured to alternate between a transmit cycle and a receive cycle;

wherein during the transmit cycle, the transmit switch is turned on and the receive switch is turned off; and

wherein during the receive cycle, the receive switch is turned on and the transmit switch is turned off.

7. A method for operating a retro-directive array, comprising:

receiving a first input signal at a first antenna comprising two or more antenna elements including at least two spatially orthogonal antenna elements, the first input signal comprising two signal components associated with different orthogonal polarizations, wherein the two signal components are received by the two spatially orthogonal antenna elements, and wherein the two signal components comprise a first quadrature signal;

feeding the two signal components through a bi-directional quadrature gain (BQG) module, the BQG module to boost the first quadrature signal; and

transmitting the boosted first quadrature signal through an associated second antenna in the retro-directive array.

8. The method of claim 7, further comprising introducing a delay into at least one of the first quadrature signal and the boosted first quadrature signal.

9. The method of claim 7, further comprising concurrently to receiving the first input signal at the first antenna:

receiving a second input signal at the second antenna, the second antenna to separate the second input signal into two signal components associated with different orthogonal polarizations, and wherein the two signal components comprise a second quadrature signal;

concurrently to feeding the quadrature signal through the BQG module, feeding the second quadrature signal through the BQG module, the BQG module to boost the second quadrature signal, wherein the second quadrature signal feeds through the BQG module in an opposite direction to the first quadrature signal; and

concurrently to transmitting the boosted quadrature signal through the BQG module, transmitting the boosted second quadrature signal through the first antenna.

10. The method of claim 7, wherein feeding a quadrature signal having two signal components through the BQG module comprises:

feeding the two signal components through a first hybrid coupler H₁ to produce a first output which is zero and a second output;

feeding the second output through a first gain element to produce a boosted second output; and

feeding the boosted second output through a second hybrid coupler H₂, which produces two signal components that comprise the boosted quadrature signal.

11. The method of claim 7, further comprising using one of a down-conversion and a self-mixing/zero IF technique within the BQG module to facilitate down-link data transfers.

12. The method of claim 7, further comprising modulating gain elements within the BQG module to facilitate up-link data transfers.

13. The method of claim 7, wherein the first antenna and the second antenna are circular-polarized antennas.

14. An apparatus which includes a retro-directive array, wherein the retro-directive array comprises:

a first antenna comprising two or more antenna elements including at least two spatially orthogonal antenna elements, the two spatially orthogonal antenna elements to receive two signal components of a first input signal associated with different orthogonal polarizations, and wherein the two signal components comprise a first quadrature signal;

a bi-directional quadrature gain (BQG) module coupled to the first antenna and configured to boost the first quadrature signal; and

a second antenna configured to transmit the boosted first quadrature signal to the tracking device.

15. The apparatus of claim 14, further comprising a delay element to introduce a delay into one of the first quadrature signal and the boosted first quadrature signal.

16. The apparatus of claim 14,

wherein concurrently with the first antenna receiving the first input signal, the second antenna is to receive a second input signal which is substantially circularly polarized, the second antenna to separate the second input signal into two signal components associated with different orthogonal polarizations, wherein the two signal components comprise a second quadrature signal;

wherein concurrently with boosting the first quadrature signal, the BQG module is to boost the second quadrature signal, which feeds through the BQG module in an opposite direction to the first quadrature signal; and

wherein the first antenna is to transmit the boosted second quadrature signal to the tracking device.

17. The apparatus of claim 16, wherein the BQG module comprises:

a first hybrid coupler H₁ to receive the two signal components from the first antenna and to produce a first output which is zero and a second output;

a first gain element to receive the second output and to produce a boosted second output;

and

a second hybrid coupler H₂ to receive the second boosted output and to produce two outputs that comprise the boosted first quadrature signal.

18. The apparatus of claim 14, wherein the BQG module is to use one of a down-conversion and a self-mixing/zero IF technique within the BQG module to facilitate downlink data transfers.

19. The apparatus of claim 14, wherein the BQG module is configured to modulate gain elements within the BQG module to facilitate up-link data transfers.

20. The apparatus of claim 14, wherein the first antenna and the second antenna are circular-polarized antennas.