Patent ID: 9577584
Date: 2017-02-21
CPC Classifications: H03F

Claim:
1. An amplifier circuit comprising: a first amplifier configured to amplify a first input signal, wherein an output of the first amplifier is coupled to an output node via a first transmission line, the first transmission line comprising a first portion having a first characteristic impedance and a first length, and a second portion having a second characteristic impedance and a second length; a second amplifier configured to amplify a second input signal, wherein an output of the second amplifier is coupled to the output node via a second transmission line, the second transmission line comprising a first portion having a first characteristic impedance and a first length, and a second portion having a second characteristic impedance and a second length; and an auxiliary amplifier configured to amplify a third input signal, wherein an output of the auxiliary amplifier is coupled via an auxiliary transmission line network to a first intersection between the first and second portions of the first transmission line, and to a second intersection between the first and second portions of the second transmission line; wherein for each of the first and second transmission lines, the first and second portions consist of a higher-impedance portion and a lower-impedance portion whose combined length is a half wavelength; and wherein the lengths of the respective first portions of the first and second transmission lines sum to half a wavelength, and the lengths of the respective second portions of the first and second transmission lines sum to half a wavelength.