Vectorially Combined Distributed Power Amplifiers for Software-Defined Radio Applications

A new technique for distributed power amplifier (DPA) design maximizing dc-RF conversion is presented. The topology is featured by the vectorial combination of the output current sources when the transistors are loaded by their distributed output networks. To verify the design concept, two prototype DPAs (a 600-mW pseudomorphic HEMT (pHEMT) DPA and a ~ 23-W pHEMT/GaN DPA) are designed, realized, built, and tested. To the authors' knowledge, the second DPA achieved state-of-the-art power performance (i.e., the combination of output power, gain, and efficiency) for DPAs within the frequency range up to 2 GHz, well suited for software-defined radio applications.