Title :
Design of variable gain amplifier with gain-bandwidth product up to 354 GHz implemented in InP-InGaAs DHBT technology
Author :
Lai, Jie-Wei ; Chuang, Yu-Ju ; Cimino, Kurt ; Feng, Milton
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Illinois, Champaign, IL, USA
Abstract :
A high-gain and wide-band variable gain amplifier (VGA) is developed using 300-GHz InP-InGaAs double-heterojunction bipolar transistor (DHBT). Negative-RE quad is used to enhance amplifier gain-bandwidth product. At maximum gain, the single-ended S21 of 17 dB and the associated 3-dB bandwidth of 50 GHz are measured to produce a gain-bandwidth product of 354 GHz in a VGA including a Gilbert multiplier and an output driver. The gain-bandwidth product is twice the value measured from the VGA designed by single resistor degeneration in the same process. The circuit is designed in terms of detailed stability considerations and the experimental results show it to be unconditionally stable over 0.5-50 GHz. The linearity of the VGA is affected by nonlinear effects in DHBTs, and different design approaches are analyzed. An output interception point of the third harmonic of 16.2 dBm is measured.
Keywords :
III-V semiconductors; bipolar transistor circuits; gallium arsenide; indium compounds; multiplying circuits; network synthesis; submillimetre wave amplifiers; wideband amplifiers; 300 GHz; 354 GHz; DHBT technology; Gilbert multiplier; InP-InGaAs; double heterojunction bipolar transistors; gain-bandwidth product; high-frequency amplifiers; high-speed integrated circuits; wide-band variable gain amplifier; Bandwidth; Bipolar transistors; Broadband amplifiers; Circuit stability; Cutoff frequency; DH-HEMTs; Gain; High speed integrated circuits; Integrated circuit technology; Resistors; Heterojunction bipolar transistors (HBTs); high-frequency amplifiers; high-speed integrated circuits;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2005.862676
