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Non-Linear effects in varactor tuned resonators

Everard, J. and Liang, Z. (2006) Non-Linear effects in varactor tuned resonators. IEEE Transaction of Ultrasonics Ferroelectrics and Frequency Control, 53 (5). 853- 860. ISSN 0885-3010

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This paper describes the effects of RF power level on the performance of varactor-tuned resonator circuits. A variety of topologies are considered, including series and parallel resonators operating in both unbalanced and balanced modes. As these resonators were designed to produce oscillators with minimum phase noise, the initial small signal insertion loss was set to 6 dB and, hence, QL /Q0 = 1/2. To enable accurate analysis and simulation, S parameter and PSPICE models for the varactors were optimized and developed. It is shown that these resonators start to demonstrate nonlinear operation at very low power levels demonstrating saturation and lowering of the resonant frequency. On occasion squegging is observed for modified bias conditions. The nonlinear effects are dependent on the unloaded Q (Q0), the ratio of loaded to unloaded Q (QL/Q0), the bias voltage, and circuit configurations with typical nonlinear effects occurring at -8 dBm in a circuit with a loaded Q of 63 and a varactor bias voltage of 3 V. Analysis, simulation, and measurements that show close correlation are presented.

Item Type: Article
Institution: The University of York
Academic Units: The University of York > Electronics (York)
Depositing User: York RAE Import
Date Deposited: 22 May 2009 15:52
Last Modified: 22 May 2009 15:52
Published Version: http://dx.doi.org/10.1109/TUFFC.2006.1632676
Status: Published
Publisher: Institute of Electrical and Electronics
Identification Number: 10.1109/TUFFC.2006.1632676
URI: http://eprints.whiterose.ac.uk/id/eprint/6256

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