High efficiency power amplifier with frequency band selective matching networks

In this article, a high efficiency power amplifier (PA) with frequency selective matching networks (MNs) that can provide passband impedance matching as well as suppression of out-of-band signals simultaneously is proposed. The proposed frequency selective MN consists of a λ/4 length coupled line, a λ/2 length open step-impedance resonator stub, and a λ/6 length bias line terminated with a bypass capacitor. For experimental validation, the PA with input and output frequency selective MNs is designed and fabricated for the US PCS band (1.93-1.99 GHz). The measurement results show that the output power and power add efficiency are 43 dBm and 70.3%, respectively, at the center frequency of 1.96 GHz, and the out-of-band suppression is higher than 32 dB.