A Triple-Band Doherty Amplifier for Mobile Applications

In this article, we present a triple-band Doherty power amplifier (DPA) with a Schiffman phase shifter, which achieved a 90-degree phase shift to facilitate broad frequency range operations. As the cornerstone of the triple-band DPA, the Schiffman phase shifter enabled simultaneous triple-band operations. Furthermore, the entire triple-band Doherty amplifier was designed and fabricated using GaN on SiC HEMT devices, confirming its practical applicability and robust performance. It achieved an output power of 34 dBm at the low-band (LB) frequency of 0.8 GHz, accompanied by a peak drain efficiency (DE) of 53%. Similarly, at the mid-band (MB) frequency of 1.6 GHz, the amplifier maintained an output power of 32 dBm with an identical peak DE of 45%. At the high-band (HB) frequency of 2.2 GHz, the DPA continued to deliver an output power of 33 dBm, again with a peak DE of 50%.