Title :
Ultrahigh power efficiency operation of common-emitter and common-base HBT´s at 10 GHz
Author :
Wang, N.L. ; Sheng, N.H. ; Chang, M.F. ; Ho, W.J. ; Sullivan, G.J. ; Sovero, E.A. ; Higgins, J.A. ; Asbeck, P.M.
Author_Institution :
Rockwell Int. Sci. Center, Thousand Oaks, CA, USA
fDate :
10/1/1990 12:00:00 AM
Abstract :
The DC and RF characteristics of microwave power HBTs are described. Ultrahigh power-added efficiency is reported for AlGaAs-GaAs HBTs operating at 10 GHz in common-emitter (CE) and common-base (CB) modes. A record high 67.8% power-added efficiency with 11.6 dB associated gain was achieved with a CE HBT at a CW output power of 0.226 W, corresponding to a power density of 5.6 W/mm. With a CB HBT, 62.3% power-added efficiency with 11.85 dB gain and 0.385 W total CW power was demonstrated. Power saturation characteristics of CE and CB HBTs are compared. The importance of bias schemes is discussed. High-efficiency operation in near class B mode is described and compared with FET operation. An advantage of HBT over FET is the low leakage current during the off half cycle in class B operation. Stability conditions for CE and CB HBTs are discussed
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; power transistors; solid-state microwave devices; 0.226 to 0.385 W; 10 GHz; 11.6 to 11.85 dB; 62.3 to 67.8 percent; AlGaAs-GaAs; CW output power; DC characteristics; HBT; RF characteristics; SHF; bias schemes; common-base; common-emitter; low leakage current; microwave power HBTs; near class B mode; power-added efficiency; ultrahigh power efficiency operation; Fabrication; Gain; Gallium arsenide; Heterojunction bipolar transistors; Microwave FETs; Microwave transistors; Power amplifiers; Power generation; Solid state circuits; Stability;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
