id: 32589
Title: Model Study of the Qfactor of a Varicap Diode by Its Equivalent Circuits
Authors: Rudyk A., Semenov A., Semenova O., Tsyrulnyk S., Tromsyuk V.
Keywords: varicap diode, Qfactor, model study, mathematical model, equivalent circuit.
Date of publication: 20230301 15:57:42
Last changes: 20230301 15:57:42
Year of publication: 2022
Summary: In this study, the authors showed that the Qfactor of a varicap diode depends on frequency and is a function of parameters of its smallsignal equivalent circuit. Influence of the equivalent circuit parameters on the varicap diode Qfactor in ranges of low and high frequencies was analyzed. Equations for determining the maximum value of the varicap diode Qfactor and a frequency that corresponds to the extreme value of the Qfactor were obtained. Theoretical results were experimentally verified for three different varicap diodes of BB1xx types manufactured by NXP Semiconductors. Deviations of theoretical results from experimental testing in the (20–500) MHz frequency range do not exceed 8.6%. For varicap diodes of BB149 and BB174 types, the frequency ranges were established, in which their Qfactor was more than 35; and for a varicap diode of BB181 type the frequency ranges were established, in which its Qfactor was more than 15. Parameters of elements of series and parallel equivalent circuits of the varicap diode were determined. Frequency dependences of active and reactive components of the series and parallel equivalent circuits of the varicap diode were analyzed. For three types of varicap diodes, frequency ranges were determined in which difference between an equivalent capacitance of the equivalent circuit and a barrier capacitance was less than 0.5%, and difference between an equivalent resistance of the equivalent circuit and a loss resistance in the emitter and base regions was less than 3%. It was proved that in the frequency range where the varicap diode Qfactor was greater than 35 (BB149 and BB174) or 15 (BB181), the equivalent capacitances of series and parallel equivalent circuits can be regarded as independent of frequency and equal to the capacitance of the varicap diode junction with an error of less than 0.5%.
URI: http://repository.vsau.org/repository/getfile.php/32589.pdf
Publication type: Статті Scopus
Publication: Workshop Proceedings. 2022. Vol. 3309. P. 396413. Code 185325
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