Doherty amplifier and communication device

Patent metadata

Field	Value
Publication number	US-2022239259-A1
Application number	US-202217722839-A
Country	US
Kind code	A1
Filing date	Apr 18, 2022
Priority date	Dec 13, 2019
Publication date	Jul 28, 2022
Grant date	—

Abstract

A Doherty amplifier is configured in such a manner that: the ratio Z3/Z2 of a characteristic impedance Z3 of a second transmission line to a characteristic impedance Z2 of a first transmission line is a power division ratio P2/P3 of a signal to be amplified between a carrier amplifier and a peak amplifier when both of the carrier amplifier and the peak amplifier are saturated; and a resistance value Riso of a resistor is a value obtained by multiplying, by a proportionality coefficient w which is equal to or greater than 0 but less than 1, the sum of the input impedance Zcin0 of the carrier amplifier when the carrier amplifier reaches saturation and the input impedance Zpin0 of the peak amplifier when the peak amplifier reaches saturation.

First claim

1 . A Doherty amplifier comprising:
a first transmission line having a first end connected to an input terminal to which a signal to be amplified is input; a second transmission line having a first end connected to the input terminal; a resistor connected between a second end of the first transmission line and a second end of the second transmission line; a carrier amplifier to amplify a signal output from the second end of the first transmission line and output the amplified signal to an output combining point; and a peak amplifier to amplify a signal output from the second end of the second transmission line and output the amplified signal to the output combining point, wherein a ratio of a characteristic impedance of the second transmission line to a characteristic impedance of the first transmission line is a power division ratio of the signal to be amplified between the carrier amplifier and the peak amplifier when both of the carrier amplifier and the peak amplifier are saturated, and a resistance value of the resistor is a value obtained by multiplying, by a proportionality coefficient that is equal to or greater than 0 but less than 1, a sum of an input impedance of the carrier amplifier when the carrier amplifier reaches saturation and an input impedance of the peak amplifier when the peak amplifier reaches saturation.

2 . The Doherty amplifier according to claim 1 , further comprising:
a coefficient adjustment line that is connected between the second end of the second transmission line and the peak amplifier and adjusts a reflection coefficient of a signal at the peak amplifier, which is obtained when the peak amplifier is viewed from the second end of the second transmission line; and a phase adjustment line that is connected between the second end of the first transmission line and the carrier amplifier and has an electrical length same as an electrical length of the coefficient adjustment line.

3 . The Doherty amplifier according to claim 1 , further comprising a capacitor connected in series with the resistor.

4 . A communication device, wherein the signal to be amplified is a communication signal, the communication device comprising the Doherty amplifier according to claim 1 as an amplifier to amplify the communication signal.

5 . A communication device, wherein the signal to be amplified is a communication signal, the communication device comprising the Doherty amplifier according to claim 2 as an amplifier to amplify the communication signal.

6 . A communication device, wherein the signal to be amplified is a communication signal, the communication device comprising the Doherty amplifier according to claim 3 as an amplifier to amplify the communication signal.

Assignees

• Mitsubishi Electric Corp

Inventors

• Sakata Shuichi
• Komatsuzaki Yuji
• Shinjo Shintaro

Classifications

• H01P5/16

  Conjugate devices, i.e. devices having at least one port decoupled from one other port · CPC title

• H03F3/602

  Combinations of several amplifiers · CPC title

• H03F1/56

  Modifications of input or output impedances, not otherwise provided for · CPC title

• H03F2200/423

  Amplifier output adaptation especially for transmission line coupling purposes, e.g. impedance adaptation · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title