Wideband filtering power amplifier based on terminated coupled line structure

This paper proposes a design method for designing a wideband filtering power amplifier (PA) based on terminated coupled line structure (TCLS). This method generates four transmission zeros and three transmission poles by loading stepped impedance resonator and short-circuit stubs on the four ports of TCLS, which greatly optimizes the in-band return loss and stopband suppression of the output matching network. In addition, the effective suppression of the second harmonic also increases the efficiency of the PA. In order to verify the effectiveness and superiority of this design method, a wideband bandpass filtering PA is designed and manufactured in 2.9–3.7 GHz. Measurement results show that the saturated output power is from 40.1 dBm to 41.2 dBm, the drain efficiency is greater than 60.3%, and the gain is 10–11.2 dB.