High efficiency single and push-pull power amplifiers

High-efficiency single and push-pull power amplifiers are constructed by using the higher harmonics along with the fundamental wave. By connecting the parallel resonators for the fundamental wave and the third harmonic to the load circuit of the amplifier, one can synthesize a square wave, which is necessary for obtaining a high-efficiency amplifier. Both the single and push-pull power amplifiers were tested at an operating frequency of 0.9 GHz. The maximum output power and power-added efficiency were 36.1 dBm and 60%, respectively, for the single amplifier and were 39 dBm and 81%, respectively, for the push-pull amplifier.<>