Radio frequency power amplifier

摘要

A radio frequency power amplifier includes: an amplifying element which amplifies an input signal and outputs the signal from an output terminal; and an output load circuit which includes a first resonant circuit and a second resonant circuit that are connected to the output terminal. The first resonant circuit has a resonance frequency higher than the frequency of the second harmonic of the input signal, and the second resonant circuit has a resonance frequency lower than the frequency of the third harmonic of the input signal. The output load circuit has such an impedance looking from the output terminal that a phase of a reflection coefficient at the second harmonic of the input signal is greater than 180 degrees and less than 360 degrees, and a phase of a reflection coefficient at the third harmonic of the input signal is greater than 0 degrees and less than 180 degrees.

主权项

1. A radio frequency power amplifier which performs class F operation, comprising:
an amplifying element which amplifies an input signal and outputs the amplified input signal from an output terminal; and an output load circuit which includes a first resonant circuit and a second resonant circuit that are connected to the output terminal, wherein the first resonant circuit has a resonance frequency higher than a frequency of a second harmonic of the input signal, the second resonant circuit has a resonance frequency lower than a frequency of a third harmonic of the input signal, and with reference to an output impedance of the amplifying element looking into the amplifying element from the output terminal of the amplifying element, the output load circuit has such an impedance looking into the output load circuit from the output terminal of the amplifying element that a phase of a reflection coefficient at the second harmonic of the input signal is greater than 180 degrees and less than 360 degrees, and a phase of a reflection coefficient at the third harmonic of the input signal is greater than 0 degrees and less than 180 degrees, each of the phase of the reflection coefficient at the second harmonic and the phase of the reflection coefficient at the third harmonic being expressed by a phase of a reflection coefficient ((z−1)/(z+1)) where z represents a normalized impedance of a load normalized by the output impedance of the amplifying element.