Design of Generalized Symmetric Doherty Power Amplifier with Device Parasitics Compensation for 5G Wireless Transmitters

The symmetric Doherty Power Amplifier (DPA) with extended output power back-off (OPBO) for 5G applications is investigated in this article. The problems experienced in the actual design phase when the design involves a high frequency and power, including device non-idealities, are examined. A parasitic compensation technique addresses the DPA issues, such as RF current leakage from the main to the auxiliary (when the aux $P A$ is not open ideally). In addition, considering the device parasitic along with the load combiner design directly matches the optimum loads $\left(R_{\text {opt} }\right.$) at saturation and $2 R_{\text {opt} }$ at back-off, omitting the design requirement of the output matching network. For the verification, A $47-\mathrm{dBm}$ peak power, DPA with $8 \mathrm{~dB}$ OPBO, operating from $3.3 \mathrm{GHz}-3.7 \mathrm{GHz}$ is designed using CG2H40025F GaN devices. Good understanding is observed between the simulated and measured results. The DPA design shows $65-75 \%$ Drain Efficiency (DE) at saturation ($\gt47$ dBm) and $45-47 \% \mathrm{DE}$ at 8 -dB back-off output power. From the author’s knowledge, this device will be a potential candidate for small base station applications.