US 12,451,844 B2
Doherty amplifier
Yuji Komatsuzaki, Tokyo (JP); Shuichi Sakata, Tokyo (JP); Shintaro Shinjo, Tokyo (JP); and Hiroshi Otsuka, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
Filed on Oct. 6, 2022, as Appl. No. 17/960,938.
Application 17/960,938 is a continuation of application No. PCT/JP2020/022180, filed on Jun. 4, 2020.
Prior Publication US 2023/0029039 A1, Jan. 26, 2023
Int. Cl. H03F 1/02 (2006.01); H03F 1/56 (2006.01); H03F 3/24 (2006.01)
CPC H03F 1/0288 (2013.01) [H03F 1/56 (2013.01); H03F 3/245 (2013.01); H03F 2200/222 (2013.01); H03F 2200/387 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A Doherty amplifier comprising:
a first amplifier to amplify a first signal as an auxiliary amplifier in a case where a frequency of each of the first signal and a second signal is a first frequency, and amplify the first signal as a main amplifier in a case where the frequency of each of the first signal and the second signal is a second frequency;
a second amplifier to amplify the second signal as a main amplifier in a case where the frequency of each of the first signal and the second signal is the first frequency, and amplify the second signal as an auxiliary amplifier in a case where the frequency of each of the first signal and the second signal is the second frequency; and
a combiner to synthesize the first signal amplified by the first amplifier and the second signal amplified by the second amplifier,
wherein the second amplifier has a saturated output power which is larger than a saturated output power of the first amplifier, and
in a case where the first amplifier amplifies the first signal as the main amplifier and the second amplifier amplifies the second signal as the auxiliary amplifier, the combiner transforms output impedance of the first amplifier so that an imaginary component in the output impedance of the first amplifier is reduced,
the combiner reduces an output reflection coefficient of the first amplifier by transforming the output impedance of the first amplifier in a case where the first amplifier amplifies the first signal as the main amplifier and the second amplifier amplifies the second signal as the auxiliary amplifier, as compared with an output reflection coefficient of the first amplifier in a case where the first amplifier amplifies the first signal as the auxiliary amplifier and the second amplifier amplifies the second signal as the main amplifier, and
a reduction amount of the output reflection coefficient based on a difference between the output reflection coefficient of the first amplifier in a case where the first amplifier amplifies the first signal as the main amplifier and the second amplifier amplifies the second signal as the auxiliary amplifier and the output reflection coefficient of the first amplifier in a case where the first amplifier amplifies the first signal as the auxiliary amplifier and the second amplifier amplifies the second signal as the main amplifier, is smaller than an increased amount of the output reflection coefficient of the first amplifier due to a difference between the saturated output power of the first amplifier and the saturated output power of the second amplifier.