A 1.8–3.2-GHz Doherty Power Amplifier in Quasi-MMIC Technology

摘要

This letter presents the design and characterization of a quasi-integrated Doherty power amplifier for base-station applications. The prototype is based on GaN on SiC 0.25-mu m 50-V transistors, whereas the passive matching networks are realized on a GaAs substrate. The design, based on a dual-input Doherty architecture, achieves a continuous-wave (CW) output power higher than 42 dBm and a backoff efficiency higher than 38% over the 1.8-3.2-GHz frequency band. By using an off-chip coupler, a single-input operation is also possible with a slight reduction in performance, i. e., CW output power and backoff efficiency higher than 41.4 dBm and 36%, respectively, on the 1.8-3.2-GHz band. System-level characterization shows higher peak power achievable than in CW condition as well as the linearizability of the amplifier under modulated signal conditions.