Design a high efficiency power amplifier by optimizing device output waveform

This paper presents the performance improvement of microwave power amplifiers (PAs) by optimizing the device output waveform. It may increase the fundamental frequency component output power and power added efficiency (PAE) by choosing the harmonic coefficient of the transistor output waveform. The analysis has been given and a design procedure has been outlined to verify the harmonic waveform effect and its impact on PA performance. We design a power amplifier which adopts the transistor NE69039 for the operation at the wideband code division multiple access (WCDMA) band of 1.92-1.98 GHz with a supply voltage of 3.6 V to illustrate cases of manipulation of the transistor collector output waveform. The obtained improvement of the power amplifier by choosing the output waveform is obvious. The amplifier PAE is 76% when the output power is 30 dBm.