Unbalanced linear power amplifier

Patent metadata

Field	Value
Publication number	US-9369095-B2
Application number	US-201514606375-A
Country	US
Kind code	B2
Filing date	Jan 27, 2015
Priority date	Jan 27, 2014
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

An unbalanced linear power amplifier (PA) is disclosed having a quadrature coupler with a 90° phase input port, a 0° phase input port, an output termination port, and a signal output port. Each of the 90° phase input port, the 0° phase input port, the output termination port, and the signal output port have a characteristic resistance (Ro). Also included is a first PA having an output coupled to a 90° phase input port of the quadrature coupler and a second PA having an output coupled to a 0° phase input port of the quadrature coupler. Biasing circuitry provides the first PA and the second PA with a similar gain. A tuning network is coupled between the output termination port and ground. The tuning network has an isolation resistance in series with an isolation inductance, wherein the isolation resistance is between about 0.02*Ro Ω and 0.8*Ro Ω.

First claim

What is claimed is:

1. An unbalanced linear power amplifier (PA) comprising:
a quadrature coupler having a 90° phase input port, a 0° phase input port, an output termination port, and a signal output port for providing an output signal, wherein each of the 90° phase input port, the 0° phase input port, the output termination port, and the signal output port have a characteristic impedance (Zo) comprising a characteristic resistance (Ro);
a first PA having an output coupled to the 90° phase input port of the quadrature coupler,
a second PA having an output coupled to the 0° phase input port of the quadrature coupler;
biasing circuitry configured to bias the first PA to provide a first gain and to bias the second PA to provide the first gain; and
a tuning network coupled between the output termination port and ground and comprising an isolation resistance in series with an isolation inductance, wherein the isolation resistance is between about 0.02*Ro Ω and 0.8*Ro Ω.

2. The unbalanced linear PA of claim 1 wherein the isolation resistance is between about 0.1Ω and 10Ω.

3. The unbalanced linear PA of claim 1 wherein the isolation resistance is between about 10Ω and 20Ω.

4. The unbalanced linear PA of claim 1 wherein the isolation resistance is between about 20Ω and 30Ω.

5. The unbalanced linear PA of claim 1 wherein the isolation resistance is between about 30Ω and 40Ω.

6. The unbalanced linear PA of claim 1 wherein the isolation inductance is between about 0.1 nH and 0.5 nH.

7. The unbalanced linear PA of claim 1 wherein the isolation inductance is between about 0.5 nH and 1 nH.

8. The unbalanced linear PA of claim 1 wherein the isolation inductance is between about 1 nH and 2 nH.

9. The unbalanced linear PA of claim 1 wherein the output signal has an error vector magnitude (EVM) of less than about 2.0%.

10. The unbalanced linear PA of claim 1 wherein the output signal has an EVM of less than about 1.8%.

11. The unbalanced linear PA of claim 1 wherein the first PA and the second PA are both biased for class A operation.

12. The unbalanced linear PA of claim 1 wherein the first PA and the second PA are both biased for class AB operation.

13. The unbalanced linear PA of claim 1 wherein the tuning network is dynamically tunable.

14. The unbalanced linear PA of claim 13 further including a controller for dynamically tuning the tuning network.

15. The unbalanced linear PA of claim 14 wherein the controller is further configured to dynamically adjust the tuning network to minimize AM-AM distortion of the output signal.

16. The unbalanced linear PA of claim 14 wherein the isolation resistance is provided by an isolation resistor with variable resistance and the controller is configured to dynamically adjust the variable resistance based upon a given frequency of the output signal.

17. The unbalanced linear PA of claim 14 wherein the isolation inductance is provided by an isolation inductor with variable inductance and the controller is configured to dynamically adjust the variable inductance based upon a given frequency of the output signal.

18. The unbalanced linear PA of claim 14 wherein the isolation resistance is provided by an isolation resistor with variable resistance and the isolation inductance is provided by an isolation inductor with variable inductance and the controller is configured to dynamically adjust both the variable resistance and the variable inductance based upon a given frequency of the output signal.

19. The unbalanced linear PA of claim 1 wherein the isolation resistance is fixed.

20. The unbalanced linear PA of claim 1 wherein the isolation inductance is fixed.

21. The unbalanced linear PA of claim 1 wherein the isolation resistance is fixed and the isolation inductance is fixed.

22. The unbalanced linear PA of claim 1 wherein the quadrature coupler is a Lange coupler.

23. The unbalanced linear PA of claim 1 wherein the output signal has a frequency between about 1.8 GHz and 2.5 GHz.

24. The unbalanced linear PA of claim 1 wherein the output signal has a frequency between about 2.5 GHz and 3.8 GHz.

25. The unbalanced linear PA of claim 1 wherein the output signal has a frequency between about 3.8 GHz and 5 GHz.

26. The unbalanced linear PA of claim 1 wherein the output signal has a frequency between about 5 GHz and 6 GHz.

27. The unbalanced linear PA of claim 1 further comprising a second quadrature coupler having a 0° phase output port coupled to an input port of the first PA, and a 90° phase output port coupled to an input port of the second PA, an input termination port, and a signal input port for receiving an input signal.

28. The unbalanced linear PA of claim 27 wherein a fixed isolation resistor is coupled between the input termination port and ground.

29. The unbalanced linear PA of claim 27 further comprising a second tuning network coupled between the input termination port and ground and comprising a second isolation inductance and a second isolation resistance in series with the second isolation inductance, wherein the second isolation resistance is between about 0.02*Ro Ω and 0.8*Ro Ω.

30. The unbalanced linear PA of claim 29 wherein the second tuning network is dynamically tunable by a controller that is configured to dynamically tune the second tuning network based upon a given frequency of the input signal.

31. The unbalanced linear PA of claim 27 wherein the second quadrature coupler is a Lange coupler.

32. The unbalanced linear PA of claim 1 wherein the characteristic resistance is between about 50Ω and 300Ω.

Assignees

• Rf Micro Devices Inc

Inventors

• Kobayashi Kevin Wesley

Classifications

• H03F1/0261

  with control of the polarisation voltage or current, e.g. gliding Class A · CPC title

• H03F3/602

  Combinations of several amplifiers · CPC title

• H03F2201/3215

  To increase the output power or efficiency · CPC title

• H03F1/32 Primary

  Modifications of amplifiers to reduce non-linear distortion (by negative feedback H03F1/34) · CPC title

• H03F2200/198

  A hybrid coupler being used as coupling circuit between stages of an amplifier circuit · CPC title