Methods and devices for in-phase and quadrature signal generation

Patent metadata

Field	Value
Publication number	US-10979038-B2
Application number	US-201916546847-A
Country	US
Kind code	B2
Filing date	Aug 21, 2019
Priority date	Aug 21, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A method for in-phase (I) and quadrature (Q) signal generation is disclosed. The method may include a first stage receiving a differential input signal. The first stage may also generate first differential in-phase and quadrature output signals, which may be sent by the first stage to a second stage. The second stage may generate second differential in-phase and quadrature output signals, which may have amplitude and phase mismatches less than an amplitude and phase mismatches of the first differential output signals. The second stage may then output the second differential I/Q output signals.

First claim

What is claimed is:

1. An in-phase and quadrature signal generation system comprising:
a first stage configured to:
receive a first set of differential input signals; and
generate a first set of differential in-phase/quadrature (I/Q) output signals; and

a second stage configured to:
receive the first set of differential I/Q output signals; and
generate a second set of differential I/Q output signals;

wherein the amplitude and phase mismatches between the second set of differential I/Q output signals is less than the amplitude and phase mismatches between the first set of differential I/Q output signals, compensating for quadrature errors of the first set of differential I/Q output signals;
wherein the first stage comprises:
a first coupled line coupler (CLC); and
a second CLC;
wherein each CLC comprises:
a pair of transmission lines close enough in proximity so when energized, energy from one of the transmission lines passes to the other transmission line;
an inlet port directly coupled to a through port across one of the pair of transmission lines;
a coupled port coupled to the inlet port; and
an isolation port directly connected to the coupled port across transmission line;
wherein the isolation port is terminated to an optimum impedance; and

wherein the signal generation system is configured to:
generate the second set of differential I/Q output signals at mm-wave frequencies; and
achieve an image rejection ratio of more than 29 across a frequency range of between 42-102 GHz.

2. The system of claim 1 , wherein the first stage is further configured to maintain the frequency of the second set of differential output signals the same as the frequency of the first set of differential I/Q input signals;
wherein the first set of differential input signals comprises a first input signal and a second input signal; and
wherein the first input signal has a phase shift relative to the second input signal.

3. The system of claim 2 , wherein the first input signal of the first set of differential input signals has a phase shift of or about 180 degrees relative to the second input signal; and
wherein the second set of differential I/Q output signals comprise:
a first output signal having a phase shift of or about ninety degrees relative to a second output signal;
the second output signal having a phase shift of or about ninety degrees relative to a third output signal;
the third output signal having a phase shift of or about ninety degrees relative to a fourth output signal; and
the fourth output signal having a phase shift of or about ninety degrees relative to the first output signal.

4. The system of claim 1 , wherein the second stage comprises a resistor-capacitor (RC) polyphase filter.

5. The system of claim 4 , wherein a physical implementation of the RC polyphase filter has a symmetrical layout with respect to a center of the polyphase filter.

6. An in-phase and quadrature signal generation system comprising:
a first stage configured to:
receive a first set of differential input signals, wherein the first set of differential input signals comprises a first input signal having a phase shift of or about 180 degrees relative to a second input signal; and
generate a first set of differential in-phase/quadrature (I/Q) output signals; and

a second stage configured to:
receive the first set of differential I/Q output signals; and
generate a second set of differential I/Q output signals comprising:
a first output signal having a phase shift of or about ninety degrees relative to a second output signal;
the second output signal having a phase shift of or about ninety degrees relative to a third output signal;
the third output signal having a phase shift of or about ninety degrees relative to a fourth output signal; and
the fourth output signal having a phase shift of or about ninety degrees relative to the first output signal

wherein the first stage is further configured to maintain the frequency of the second set of differential I/Q output signals the same as the frequency of the first set of differential I/Q input signals;
wherein the amplitude and phase mismatches between the second set of differential I/Q output signals is less than the amplitude and phase mismatches between the first set of differential I/Q output signals, compensating for quadrature errors of the first set of differential I/Q output signals;
wherein the second stage comprises:
a first coupled line coupler (CLC);
a second CLC;
a third CLC; and
a fourth CLC;
wherein each CLC comprises:
a pair of transmission lines close enough in proximity so when energized, energy from one of the transmission lines passes to the other transmission line;
an inlet port directly coupled to a through port across one of the pair of transmission lines;
a coupled port coupled to the inlet port; and
an isolation port directly connected to the coupled port across transmission line;
wherein the isolation port is terminated to an optimum impedance; and

wherein the signal generation system is configured to:
generate the second set of differential I/Q output signals at mm-wave frequencies; and
achieve an image rejection ratio of more than 29 across a frequency range of between 42-102 GHz.

7. The system of claim 6 , wherein:
the coupled port of the second CLC is connected to the through port of the first CLC;
the coupled port of the third CLC is connected to the through port of the second CLC;
the coupled port of the fourth CLC is connected to the through port of the third CLC; and
the coupled port of the first CLC is connected to the through port of the fourth CLC.

8. A receiver comprising:
an antenna configured to receive signals;
an amplifier configured to receive signals from the antenna;
an in-phase down-conversion path comprising:
a first mixer;
a first filter; and
a first baseband unit;

a quadrature down-conversion path comprising:
a second mixer;
a second filter; and
a second baseband unit; and

an in-phase and quadrature (I/Q) signal generation path comprising:
a synthesizer; and
the signal generation system of claim 6 ;
wherein the signal generation system is configured to generate:
differential in-phase (I) local oscillator (LO) signals (ILO signals); and
differential quadrature (Q) local oscillator (LO) signals (QLO signals).

9. A transmitter comprising:
an antenna configured to transmit signals;
an amplifier configured to send signals to the antenna;
an in-phase up-conversion path comprising:
a first mixer;
a first filter; and
a first baseband unit;

a quadrature up-conversion path comprising:
a second mixer;
a second filter; and
a second baseband unit; and

an in-phase and quadrature (I/Q) signal generation path comprising:
a synthesizer; and
the signal generation system of claim 6 ;
wherein the signal generation system is configured to generate:
differential in-phase (I) local oscillator (LO) signals (ILO signals); and
differential quadrature (Q) local oscillator (LO) signals (QLO signals).

10. An in-phase and quadrature signal generation system comprising:
a first stage configured to:
receive a first set of differential input signals; and
generate a first set of differential in-phase/quadrature (I/Q) output signals; and

a second stage configured to:
receive the first set of differential I/Q output signals; and
generate a second set of differential I/Q output signals;

wherein the amplitude and phase mismatches between the second set of differential I/Q output signals is less than the amplitude and phase mismatches between the first set of differential I/Q output signals, compensating for quadrature

Assignees

• Georgia Tech Res Inst

Inventors

• Frounchi Milad
• Cressler John D

Classifications

• H03K5/13 Primary

  Arrangements having a single output and transforming input signals into pulses delivered at desired time intervals · CPC title

• H03K2005/00286

  Phase shifter, i.e. the delay between the output and input pulse is dependent on the frequency, and such that a phase difference is obtained independent of the frequency · CPC title

• H03H7/21

  providing two or more phase shifted output signals, e.g. n-phase output · CPC title

• H03H2007/0192

  Complex filters · CPC title

• H03H7/06

  including resistors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title