Doherty power amplifier with integrated second harmonic injection

Patent metadata

Field	Value
Publication number	US-12088254-B2
Application number	US-202117222371-A
Country	US
Kind code	B2
Filing date	Apr 5, 2021
Priority date	May 8, 2018
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

Examples disclosed herein relate to a Doherty Power Amplifier (“DPA”) with integrated second harmonic injection. The DPA includes an amplifier circuit having a carrier amplifier and a peaking amplifier, and a combiner network coupled to the amplifier circuit, the combiner network having a plurality of transmission lines and a LC resonant circuit to inject a second harmonic from the carrier amplifier into the peaking amplifier.

First claim

What is claimed is:

1. A Doherty Power Amplifier (“DPA”), comprising:
an amplifier circuit comprising a first amplifier and a second amplifier; and
a combiner network coupled to the amplifier circuit and configured to inject a second harmonic from the first amplifier into the second amplifier, the combiner network comprising an impedance transformer with a first and a second varactor in parallel,
wherein the combiner network further comprises a λ/4 transmission line or a λ/8 transmission line in parallel with a resonant circuit.

2. The DPA of claim 1 , wherein the amplifier circuit further comprises a splitter to split an RF input signal into a first and a second signal 90° out of phase, the first signal input into the first amplifier and the second signal input into the second amplifier.

3. The DPA of claim 1 , wherein the combiner network comprises both the λ/4 transmission line and the λ/8 transmission line.

4. The DPA of claim 1 , wherein the λ/4 transmission line is coupled to an output of the first amplifier to an output of the second amplifier.

5. A Doherty Power Amplifier (“DPA”), comprising:
an amplifier circuit comprising a first amplifier and a second amplifier; and
a combiner network coupled to the amplifier circuit and configured to inject a second harmonic from the first amplifier into the second amplifier, the combiner network comprising an impedance transformer with a first and a second varactor in parallel, wherein a resonant circuit comprises an open circuit at a fundamental frequency or a short circuit at the second harmonic.

6. The DPA of claim 5 , wherein the second harmonic from the first amplifier is injected at an output of the second amplifier at back-off.

7. A combiner network, comprising:
a first λ/4 transmission line coupled to a first amplifier and a second amplifier;
a second λ/4 transmission line coupled between the second amplifier and a splitter, the splitter being coupled to the first amplifier and the second amplifier;
at least one λ/8 transmission line coupled to the first λ/4 transmission line; and
a resonant circuit in parallel with the at least one λ/8 transmission line,
wherein the resonant circuit comprises a series LC resonant circuit coupled to a parallel LC resonant circuit.

8. The combiner network of claim 7 , wherein the splitter splits an RF input signal into a first and a second signal, the first signal input into the first amplifier and the second signal input into the second amplifier.

9. A combiner network, comprising:
a first λ/4 transmission line coupled to a first amplifier and a second amplifier;
a second λ/4 transmission line coupled between the second amplifier and a splitter, the splitter being coupled to the first amplifier and the second amplifier;
at least one λ/8 transmission line coupled to the first λ/4 transmission line; and
a resonant circuit in parallel with the at least one λ/8 transmission line, wherein the resonant circuit comprises an open circuit at a fundamental frequency and a short circuit at the second harmonic.

10. The combiner network of claim 7 , wherein one of the at least one λ/8 transmission line is coupled to a load.

11. The combiner network of claim 7 , wherein the first λ/4 transmission line provides a 90° phase shift.

12. A combiner network, comprising:
a first λ/4 transmission line coupled to a first amplifier and a second amplifier;
a second λ/4 transmission line coupled between the second amplifier and a splitter, the splitter being coupled to the first amplifier and the second amplifier;
at least one λ/8 transmission line coupled to the first λ/4 transmission line; and
a resonant circuit in parallel with the at least one λ/8 transmission line, wherein the first λ/4 transmission line or the at least one λ/8 transmission line comprises an impedance transformer with a first and a second varactor in parallel.

13. A method, comprising:
splitting an RF signal into a first signal and a second signal;
injecting the first signal to a first amplifier of an amplifier circuit;
injecting the second signal to a second amplifier of the amplifier circuit; and
injecting a second harmonic from the first amplifier into the second amplifier via a combiner network coupled to the amplifier circuit,
wherein the combiner network comprises a resonant circuit and at least one λ/8 transmission line in parallel with the resonant circuit.

14. The method of claim 13 , wherein the second harmonic is injected into the second amplifier during an isolation from a load.

15. The method of claim 13 , wherein the first signal and the second signal are 90° out of phase.

16. The method of claim 13 , wherein the at least one λ/8 transmission line comprises an impedance transformer with a first and a second varactor in parallel.

17. The method of claim 13 , wherein the combiner network further comprises a λ/4 transmission line coupled to the amplifier circuit and in parallel with the resonant circuit.

18. The method of claim 13 , wherein the resonant circuit comprises a series LC resonant circuit coupled to a parallel LC resonant circuit.

Assignees

• Pivotal Commware Inc

Inventors

• Dani Asmita

Classifications

• H03F2203/21139

  An impedance adaptation circuit being added at the output of a power amplifier stage · CPC title

• H03F2200/171

  A filter circuit coupled to the output of an amplifier · CPC title

• H03F2203/21157

  A filter circuit being added at the output of a power amplifier stage · CPC title

• H03F2203/21142

  Output signals of a plurality of power amplifiers are parallel combined to a common output · CPC title

• H03F2200/387

  A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier · CPC title