Bandwidth-extended Doherty power amplifier

Patent metadata

Field	Value
Publication number	US-9450543-B2
Application number	US-201214367098-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Dec 29, 2011
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

The present invention provides a new structure of Doherty power amplifier. The present invention reduces use of ¼ wavelength lines and lowers the Q point of the Doherty power amplifier. The present method extends the DPA bandwidth with a simpler and more convenient design and facilitates the design of a narrowed size.

First claim

What is claimed is:

1. A Doherty power amplifier, comprising an input power divider into which an input signal of the Doherty power amplifier is inputted, one output of the input power divider being connected to a carrier amplifier, the other output of the divider being connected to a first ¼ wavelength line, the other end of the first ¼ wavelength line being connected to a peaking amplifier, one end of the carrier amplifier being connected to a second ¼ wavelength line, the other end of the second ¼ wavelength line being connected to the peaking amplifier; a junction point between the second ¼ wavelength line and the peaking amplifier being a signal output point of the Doherty power amplifier, wherein a characteristic impedance Z 01 of the second ¼ wavelength line is determined by the following equation:
Z 01 =50*√{square root over ((1+γ))},

where, γ is a power ratio.

2. A Doherty power amplifier, comprising an input power divider into which an input signal of the Doherty power amplifier is inputted, one output of the input power divider being connected to a carrier amplifier, the other output of the divider being connected to a first ¼ wavelength line, the other end of the first ¼ wavelength line being connected to a peaking amplifier, one end of the carrier amplifier being connected to a second ¼ wavelength line, the other end of the second ¼ wavelength line being connected to the peaking amplifier; a junction point between the second ¼ wavelength line and the peaking amplifier being a signal output point of the Doherty power amplifier, wherein a load impedance Z 02 of the peaking amplifier is determined by the following equation:

Z
02

=

50
*

(

1
+
γ

)

γ

,

where, γ is a power ratio.

3. A Doherty power amplifier, comprising an input power divider into which an input signal of the Doherty power amplifier is inputted, one output of the input power divider being connected to a carrier amplifier, the other output of the divider being connected to a first ¼ wavelength line, the other end of the first ¼ wavelength line being connected to a peaking amplifier, one end of the carrier amplifier being connected to a second ¼ wavelength line, the other end of the second ¼ wavelength line being connected to the peaking amplifier; a junction point between the second ¼ wavelength line and the peaking amplifier being a signal output point of the Doherty power amplifier, wherein when the input signal is small, the peaking amplifier is closed, and the carrier amplifier works in a high-impedance state, the impedance of the carrier amplifier being determined by the following equation:
Z high _ impedance =50* (1+γ),

where, γ is a power ratio.

Assignees

• Alcatel Lucent

Inventors

• Yang Yang
• Liu Lintao
• Guo Xianguang
• Jin Kaijie
• Yang Zhengde
• Zhong Qiu

Classifications

• H03F1/48

  of aperiodic amplifiers · CPC title

• H03F3/19 Primary

  with semiconductor devices only · CPC title

• H03F1/42

  Modifications of amplifiers to extend the bandwidth · CPC title

• H03F1/07 Primary

  Doherty-type amplifiers · CPC title

• H03F3/211

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