Inverse class‐ F X ‐band S i G e HBT power amplifier with 44% PAE and 24.5 d B m peak output power

• Published in: Microwave and optical technology letters Vol. 58; no. 12; pp. 2868 - 2871
• Main Authors: Song, Ickhyun, Ulusoy, Ahmet Çağrı, Oakley, Michael A., Ju, Inchan, Cho, Moon‐Kyu, Cressler, John D.
• Format: Journal Article
• Language: English
• Published: 01.12.2016
• ISSN: 0895-2477; 1098-2760
• DOI: 10.1002/mop.30177

ABSTRACT An X‐band power amplifier (PA) implemented in a silicon‐germanium (SiGe) heterojunction bipolar transistor technology is presented. The SiGe PA was designed for inverse class‐F mode using thin‐film microstrip (TFMS) lines, eliminating the use of conventional band‐limiting lumped inductors and transformers. Thus, simultaneous high efficiency and minimized in‐band variation were achieved for X‐band (8–12 GHz) applications. In addition, for boosting peak output power ( P out ), the common‐base transistor in the PA core was designed to operate in a weak avalanche region, which allowed dynamic collector‐to‐base voltage to swing beyond the collector‐base breakdown voltage with open emitter without performance degradation. The fabricated SiGe PA demonstrates a high power‐added efficiency (PAE) of 43.2% and a peak P out of 24.3 dBm at 10 GHz. Benefitting from the utilization of TFMS lines, the PA exhibits a flat response for both PAE (33.3–44%) and peak P out (23.1–24.5 dBm) for the entire X‐band frequency range. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2868–2871, 2016