By Topic

Efficiency enhanced and harmonic suppressed differential VCO with novel buffer scheme using transformers for IEEE 802.11a

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
Yoon, S.-W. ; Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA ; Hong, S. ; Laskar, J.

We propose a novel buffer scheme for cross-coupled differential Voltage-Controlled-Oscillator (VCO) design. Transformers are used for the new buffer configuration. The primary coil of the transformer is the inductor of the LC resonator, and the oscillation signal is extracted through the secondary. We also implement differential VCOs using a conventional buffer, and compare the performance with that of VCOs with a transformer buffer. With transformer buffers, we achieve a fivefold efficiency enhancement and 9 dBc more harmonic suppression than the conventional structure. The conventional type VCO shows an oscillation frequency of 4.4/spl sim/5.4 GHz with approximately 0 dBm output power using a total current of 15 mA. The transformer buffer VCO shows 4.7/spl sim/5.1 GHz with 6.5/spl plusmn/1 dBm output power using only 10 mA for the cross-coupled core. The 2/sup nd/ harmonic suppression of each VCO shows -10 dBc and -19 dBc, respectively. Both show a phase noise of about -111 dBc/Hz at 1 MHz offset. To the best of our knowledge, this is the first demonstration of enhancing efficiency and linearity in a VCO using transformers as a buffer stage.

Published in:

Microwave Symposium Digest, 2003 IEEE MTT-S International  (Volume:3 )

Date of Conference:

8-13 June 2003