Skyworks Solutions, Inc.
Active harmonic filters for integrated radio frequency amplifiers

Abstract:

A radio frequency front end circuit includes an output signal transmission line, an amplifier circuit with an input connected to a radio frequency signal source and an output connected to the output signal transmission line. A harmonic suppression circuit is connected to the amplifier circuit, and includes an active circuit element having a frequency-dependent impedance and is tuned as a reflective trap with a negative capacitance for one or more rejection frequency ranges each corresponding to a multiple of a fundamental frequency of a signal generated by the radio frequency signal source.