90-degree lumped and distributed Doherty impedance inverter

Patent metadata

Field	Value
Publication number	US-11722101-B2
Application number	US-202117554617-A
Country	US
Kind code	B2
Filing date	Dec 17, 2021
Priority date	Feb 2, 2017
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

Apparatus and methods for a modified Doherty amplifier operating at gigahertz frequencies are described. The combining of signals from a main amplifier and a peaking amplifier occur prior to impedance matching of the amplifier's output to a load. An output impedance-matching element can be relied upon. In one example, the output impedance-matching element can include an output strip line, a shunt capacitor connected between the output strip line and ground, an output capacitor connected between the output strip line and an output bonding pad, and an inductive strip line connected between the output bonding pad and ground.

First claim

What is claimed is:

1. A Doherty amplifier comprising:
an RF input;
a main amplifier connected to the RF input;
a peaking amplifier connected to the RF input;
an impedance inverter comprising an integrated distributed inductor connected between an output of the main amplifier and an output of the peaking amplifier; and
an output impedance-matching element comprising an output strip line, a shunt capacitor connected between the output strip line and ground, an output capacitor connected between the output strip line and an output bonding pad, and an inductive strip line connected between the output bonding pad and ground.

2. The Doherty amplifier of claim 1 , wherein:
the shunt capacitor is connected between the output strip line and a via to ground; and
the inductive strip line is connected between the output bonding pad and the via to ground.

3. The Doherty amplifier of claim 1 , wherein the impedance inverter comprises one or more bond wires connected to the output of the main amplifier.

4. The Doherty amplifier of claim 3 , wherein the impedance inverter further comprises one or more additional bond wires connected to the output the peaking amplifier.

5. The Doherty amplifier of claim 1 , wherein there are no impedance-matching elements connected between the main amplifier and the impedance inverter.

6. The Doherty amplifier of claim 1 , wherein the impedance inverter rotates a phase of a first signal amplified by the main amplifier by no more than 95 degrees with respect to a phase of a second signal amplified by the peaking amplifier.

7. The Doherty amplifier of claim 1 , wherein the integrated distributed inductor comprises a conductive strip line on a substrate.

8. The Doherty amplifier of claim 7 , wherein a width of the conductive strip line is between 100 and 1000 microns.

9. The Doherty amplifier of claim 8 , wherein a length of the conductive strip line is between 2 and 6 millimeters.

10. The Doherty amplifier of claim 1 , wherein the integrated distributed inductor comprises a first integrated distributed inductor, a second integrated distributed inductor, and a capacitor connected in series between the first integrated distributed inductor and the second integrated distributed inductor.

11. The Doherty amplifier of claim 1 , further comprising:
a combining node at which the output of the main amplifier combines with the output of the peaking amplifier, wherein
the combining node comprises a drain bonding pad of the peaking amplifier.

12. The Doherty amplifier of claim 1 , wherein one or both of the main amplifier and peaking amplifier comprises gallium-nitride transistors.

13. The Doherty amplifier of claim 1 , wherein the impedance inverter consists essentially of:
a conductive strip line having a width and a length integrated on a substrate;
bond wires connected between the conductive strip line and outputs from the main amplifier and the peaking amplifier; and
drain-to-source capacitances of the main amplifier and the peaking amplifier.

14. The Doherty amplifier of claim 1 , wherein the output impedance-matching element provides an output impedance of approximately 50 ohms for the Doherty amplifier.

15. The Doherty amplifier of claim 1 , wherein an RF fractional bandwidth for the Doherty amplifier is between approximately 6% and approximately 18%.

16. The Doherty amplifier of claim 1 , wherein an operating frequency for the Doherty amplifier is between approximately 500 MHz and approximately 6 GHz.

17. The Doherty amplifier of claim 1 , wherein a rated output power level of the amplifier is between 20 and 100 Watts.

18. A method for amplifying signals comprising:
splitting a received signal into a first signal and a second signal having a first phase with respect to the first signal;
amplifying the first signal with a main amplifier;
amplifying the second signal with a peaking amplifier;
providing an output from the main amplifier to an input of an impedance inverter, wherein the impedance inverter comprises an integrated distributed inductor;
introducing a second phase that compensates for the first phase with the impedance inverter;
combining an output from the impedance inverter with an output from the peaking amplifier; and
providing the combined output to an output impedance-matching element, the output impedance-matching element comprising an output strip line, a shunt capacitor connected between the output strip line and ground, an output capacitor connected between the output strip line and an output bonding pad, and an inductive strip line connected between the output bonding pad and ground.

19. The method of claim 18 , wherein:
the shunt capacitor is connected between the output strip line and a via to ground; and
the inductive strip line is connected between the output bonding pad and the via to ground.

Assignees

• Macom Tech Solutions Holdings Inc

Inventors

• Bouisse Gerard
• Alexander Andrew
• Patterson Andrew

Classifications

• H10W44/234

  Arrangements for impedance matching · CPC title

• H10W44/206

  Wires · CPC title

• H10W44/20

  at high-frequency [HF] or radio frequency [RF] · CPC title

• H03F1/0288 Primary

  using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers · CPC title

• H01L23/66

  Electricity · mapped topic