A Second Harmonic Amplitude Conversion Circuit for Power Amplifier

This paper proposes a second harmonic amplitude conversion circuit for power amplifier, the operating frequency band of this conversion circuit ranges from 5.5 GHz to 6 GHz. In order to reduce the complexity of signal processing encountered by digital pre-distortion technology, the circuit proposed in this paper is based on the injection-locked frequency divider, and proportionally convert the signal amplitude at second harmonic frequency into the signal amplitude at fundamental frequency. Using this technology, the second harmonic distortion signal could be observed through the injection-locked frequency divider output signal. Therefore, it could effectively reduce the complexity of the digital pre-distortion signal processing. The circuit simulation results show that for an input signal with a frequency of 11.6G, a frequency of 5.8G signal which proportional to the amplitude of the input signal is generated at the output.