A GaN-on-Si Doherty-Like Power Amplifier With Nonimpedance-Inverter Transmission Line for Smart Mobile Handset

A compact n77-band Doherty-like power amplifier (DLPA) using a 250 nm 5-V GaN-on-Si process is presented for smart handsets. To achieve miniaturization, a nonimpedance-inverter network (NIIN) in the carrier PA and an active phase-controlling technique (APCT) at the input are proposed, especially for the 3.5-dB output back-off (OBO) region, leading to the elimination of the $\lambda $ /4 inverter. Furthermore, a simplified nonorthogonal coupler with interstage networks is integrated into the APCT to ensure proper load modulation. For verification, the DLPA delivers 34.7–35 dBm saturated output power and 41.4%–44.7% efficiency at 3.5-dB OBO with a core area of $1.2\times 1.2$ mm². Driven by a 100-MHz 5G NR signal, the DLPA achieves an adjacent channel leakage ratio (ACLR) of −37.5 to −38.8 dBc with digital predistortion (DPD). To the best of our knowledge, it is the first published demonstration of a 5-V GaN-on-Si DLPA applied to smart mobile handsets.