Doherty combiner

Patent metadata

Field	Value
Publication number	US-11201592-B2
Application number	US-201716641214-A
Country	US
Kind code	B2
Filing date	Oct 23, 2017
Priority date	Aug 23, 2017
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

The present invention relates to a Doherty combiner used in a Doherty power amplifier, the Doherty combiner comprising: a phase shift section connected to one end of a carrier amplifier so as to change a phase of an RF signal output from the carrier amplifier; a matching section connected to an output terminal of the Doherty power amplifier so as to impedance-match an output of the Doherty power amplifier; and a bandwidth improvement section connected to one end of a peaking amplifier so as to change at least one of a phase bandwidth and an amplitude bandwidth of the Doherty power amplifier.

First claim

What is claimed is:

1. A Doherty combiner comprising:
a phase shift section connected between one end of a carrier amplifier and a common node so as to change a phase of an RF signal output from the carrier amplifier;
a matching section connected between the common node and an output terminal of a Doherty power amplifier so as to impedance-match an output of the Doherty power amplifier; and
a bandwidth improvement section connected between one end of a peaking amplifier and the common node so as to change at least one of a phase bandwidth and a magnitude bandwidth of the Doherty power amplifier,
wherein the common node indicates one point where one end of the phase shift section, one end of the matching section, and one end of the bandwidth improvement section meet one another.

2. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a 180° phase shift line.

3. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a 180° phase shift line connected to one end of the peaking amplifier and a parallel resonant circuit connected to the 180° phase shift line.

4. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a 180° phase shift line connected to one end of the peaking amplifier and a short stub connected to the 180° phase shift line.

5. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a serial resonant circuit in which an inductor L and a capacitor C are connected in series.

6. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a serial resonant circuit in which a first inductor and a first capacitor are connected in series and a parallel resonant circuit in which a second inductor and a second capacitor are connected in parallel.

7. The Doherty combiner of claim 5 , wherein the phase shift section includes a first transmission line for combining outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second transmission line for impedance-matching the output of the Doherty power amplifier.

8. The Doherty combiner of claim 5 , wherein the phase shift section includes first lumped elements having an equivalent relationship to a transmission line for combining the outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second lumped element having an equivalent relationship to a transmission line for impedance-matching the output of the Doherty power amplifier.

9. The Doherty combiner of claim 8 , wherein the first lumped element is configured by any one of a Low-Pass π Type LC circuit, a High-Pass π Type LC circuit, a Low-Pass T Type LC circuit, and a High-Pass T Type LC circuit, and
the second lumped element is configured by any one of a Low-Pass π Type LC circuit, a High-Pass π Type LC circuit, a Low-Pass T Type LC circuit, and a High-Pass T Type LC circuit.

10. The Doherty combiner of claim 9 , wherein the second lumped element has a different L/C value from the first lumped element.

11. The Doherty combiner of claim 5 , wherein the phase shift section includes a first lumped element and a first resonant circuit having the equivalent relationship to the transmission line for combining the outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second lumped element and a second resonant circuit having the equivalent relationship to the transmission line for impedance-matching the output of the Doherty power amplifier.

12. The Doherty combiner of claim 11 , wherein when the first or second lumped element is a π type structure, the first or second resonant circuit is the parallel resonant circuit, and
when the first or second lumped element is a T type structure, the first or second resonant circuit is the serial resonant circuit.

13. The Doherty combiner of claim 11 , wherein the second resonant circuit has the same L/C value as the first resonant circuit.

14. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a serial resonant circuit in which the inductor and the capacitor are connected in series and a short stub connected to the serial resonant circuit.

15. The Doherty combiner of claim 1 , wherein the bandwidth improvement section includes a distributed element circuit having the equivalent relationship to a lumped element circuit corresponding to the serial resonant circuit.

16. The Doherty combiner of claim 15 , wherein the distributed element circuit includes two transmission lines and capacitors equally substituted by Kuroda's Identities.

17. The Doherty combiner of claim 6 , wherein the phase shift section includes a first transmission line for combining outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second transmission line for impedance-matching the output of the Doherty power amplifier.

18. The Doherty combiner of claim 6 , wherein the phase shift section includes first lumped elements having an equivalent relationship to a transmission line for combining the outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second lumped element having an equivalent relationship to a transmission line for impedance-matching the output of the Doherty power amplifier.

19. The Doherty combiner of claim 6 , wherein the phase shift section includes a first lumped element and a first resonant circuit having the equivalent relationship to the transmission line for combining the outputs of the carrier amplifier and the peaking amplifier, and
the matching section includes a second lumped element and a second resonant circuit having the equivalent relationship to the transmission line for impedance-matching the output of the Doherty power amplifier.

Assignees

• Univ Soonchunhyang Ind Acad Coop Found

Inventors

• Ahn Dal
• Choi Kwan-Sun
• Lim Jong-Sik
• Han Sang-Min
• Kim Sung-Min
• Jang You-Na
• Lee Dae-Ung
• Oh Jun-Seok
• Koo Seo
• Kang Tae-Hoon
• Kim Ji-Won
• Jang Ik-Soo

Classifications

• 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

• H03F1/565

  using inductive elements · CPC title

• H03F2203/45501

  the CSC comprising a L-C parallel resonance circuit · CPC title

• H03F3/245 Primary

  with semiconductor devices only · CPC title

• H03F3/211

  using a combination of several amplifiers (H03F3/60 takes precedence) · CPC title