High pass output matching technique with enhanced third harmonic rejection for CDMA power amplifiers

This paper presents an alternative output matching technique using high pass configuration with improved third harmonic rejection characteristics for high-power amplifiers. By adding very small capacitor to the conventional high pass output matching circuits, phase of the third harmonic termination could be adjusted to have better performance. With an improved third harmonic rejection, we demonstrated better power-added efficiency(PAE) and linearity i.e. adjacent channel power ratio(ACPR) at the same time through the stringent trade-off of efficiency versus linearity. US-PCS (1850-1910MHz) power amplifier module employing the proposed output matching circuits is showing 1.23% higher PAE and 4.0dB better ACPR than the counterpart without an additional third harmonic rejection circuit.