Title :
Design and Analysis of Broadband Darlington Amplifiers With Bandwidth Enhancement in GaAs pHEMT Technology
Author :
Nikandish, Gholamreza ; Medi, Ali
Author_Institution :
Dept. of Electr. Eng., Sharif Univ. of Technol., Tehran, Iran
Abstract :
This paper presents a bandwidth enhancement technique for broadband Darlington amplifiers. A detailed analysis of the high-frequency performance of the Darlington amplifier and the effect of bandwidth enhancement is provided. A design procedure is also given for broadband feedback Darlington amplifiers with bandwidth enhancement and gain flattening. A single- and a three-stage feedback amplifier with the proposed improvements are designed and implemented in a 0.25- μm AlGaAs-InGaAs pHEMT technology. The single-stage amplifier provides 6±0.4 dB of small-signal gain in the frequency band of 1-30 GHz. The three-stage amplifier features 17.8±0.8 dB of small-signal gain in the frequency band of 2-29 GHz. It provides a gain-bandwidth product of 217 GHz, which is 3.3 times larger than the unity gain frequency (fT) of the process.
Keywords :
III-V semiconductors; UHF amplifiers; UHF field effect transistors; aluminium compounds; feedback amplifiers; gallium arsenide; high electron mobility transistors; indium compounds; microwave amplifiers; microwave field effect transistors; millimetre wave amplifiers; millimetre wave field effect transistors; wideband amplifiers; AlGaAs-InGaAs; bandwidth 217 GHz; bandwidth enhancement technique; broadband feedback Darlington amplifier; frequency 1 GHz to 30 GHz; gain flattening; gain-bandwidth product; pHEMT technology; single-stage feedback amplifier; size 0.25 mum; three-stage feedback amplifier; Admittance; Bandwidth; Broadband communication; Capacitance; Logic gates; Transconductance; Transistors; Bandwidth enhancement; Darlington amplifier; broadband amplifiers; feedback amplifiers; monolithic microwave integrated circuit (MMIC);
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2014.2328972
