Design of continuous-mode GaN power amplifier with compact fundamental impedance solutions on package plane

A novel methodology for designing broadband Class-J power amplifiers (PAs) with compact fundamental impedances on the package plane is presented. A simple transistor model with knee voltage region is built to predict efficiency performance and clipping waveforms caused by the clipping effects. To realise the proposed impedance solutions, a broadband matching network is presented based on the shot-stepped Chebyshev impedance transformer. A broadband Gallium Nitride (GaN) PA is designed using this method and achieve a very wide operation band from 0.8 to 3.6 GHz. More than 10 dB gain, 55.8-74.1% drain efficiency and around -30 dBc adjacent channel power ratio are measured without linearisation throughout the entire band. At 33 dBm average output power level, an average power-added efficiency of 27% and adjacent power leakage ratio of -46.3 dBc is obtained with 9 dB peak-to-average power ratio 20 MHz long-term evolution test signals at 2.4 GHz.