Copyright © 2008 The Institute of Electronics, Information and Communication Engineers
Special Section on Analog Circuits and Related SoC Integration Technologies - Papers |
Spatial Sensitivity of Capacitors in Distributed Resonators and Its Application to Fine and Wide Frequency Tuning Digital Controlled Oscillators
1 The authors are with the Department of Physical Electronics, Tokyo Institute of Technology, Tokyo, 158-8552 Japan. E-mail: win_chaivipas{at}ssc.pe.titech.ac.jp
| Abstract |
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Analysis of resonance frequency in shorted transmission lines with inserted capacitor has been made. The analysis shows a resonance frequency dependence on capacitance position on a shorted transmission line. Two analysis methods are presented to predict the resonance frequency and understand how the inserted capacitor affects the resonance frequency of the shorted transmission line. Using this knowledge we propose a new structure for digital controlled oscillators utilizing the capacitance's sensitivity dependence on position of the shorted transmission line to increase the frequency resolution. A 9 GHz transmission line based digital controlled oscillator was designed and fabricated as a proof of concept. Measured results show that more than 100 times frequency step resolution increase is possible utilizing the same tuning capacitor size located at different points on the transmission line.
Key Words: digital controlled oscillators, transmission line, frequency tuning
Manuscript received October 10, 2007. Manuscript revised December 21, 2007.