A Novel Differential Push-Pull Amplifier Based on N-Type GaAs HBT

A novel differential push-pull power amplifier structure is designed with N-type GaAs HBT technology. The circuit consists of primary input stage and two groups of push-pull amplifiers. The input stage provides a pair of differential mode signals with opposite phase and same amplitude. With a 1.8GHz-2.4GHz operating band, the amplifier demonstrates 36dBm output power, 50% PAE and 25.5dB power gain with 12V supply at 2.1GHz. Compared with the traditional N-type push-pull amplifier, the new structure improves the swing and the symmetry of the output waveform. When working at 2.1GHz, a difference of 1.019V is observed between the positive and negative half cycle output. This performance corresponds to an improvement of 0.857V compared with the traditional structure.