Title :
Design of an original K-band active balun with improved broadband balanced behavior
Author :
Viallon, C. ; Venturin, D. ; Graffeuil, J. ; Parra, T.
Author_Institution :
Lab. of Anal. & Archit. of Syst., Paul Sabatier Univ., Toulouse, France
fDate :
4/1/2005 12:00:00 AM
Abstract :
This letter deals with the design of an active balun exhibiting a single-ended input and balanced outputs. We propose an original method, based on the determination of specific impedance for connecting the differential transistor pair to ground, which greatly improves the balanced behavior over a broadband frequency range. The usefulness of this method is demonstrated through a 180/spl deg/ power divider implemented on a 0.25-μm SiGe BiCMOS process. According to simulations, measurements confirm a broadband well balanced behavior, since the power splitter exhibits phase and amplitude errors between the two channels less than 4/spl deg/ and 0.5dB, respectively, from 0.2 to 22 GHz. These errors are only 0.75/spl deg//0.03 dB in a 2-GHz span around 20 GHz, in accordance with our optimization goals.
Keywords :
BiCMOS integrated circuits; Ge-Si alloys; baluns; differential amplifiers; power dividers; 0.2 to 22 GHz; 0.25 micron; BiCMOS process; K-band; SiGe; active balun; active coupler; amplitude error; broadband balanced behavior; broadband frequency range; common mode rejection ratio; differential amplifier; differential transistor; phase error; power divider; power splitter; BiCMOS integrated circuits; Frequency; Germanium silicon alloys; Impedance matching; Joining processes; K-band; Phase measurement; Power dividers; Power measurement; Silicon germanium; Active coupler; balun; common mode rejection ratio; differential amplifier;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2005.845749