Improving Parameters of Resonator on Open- and Short-Circuited Stubs



resonator, transmission line, open-circuited stub, short-circuited stub


Introduction. Resonators are used for narrowband filtering and signal generation. Resonator on open-circuited stubs is widely used. Compared to this resonator, a resonator on open- and short-circuited stubs has the following advantages: twice as short; there are no responses at zero and doubled frequencies. However, due to a significant disadvantage — very small length of the short-circuited stub — such a resonator has not become widespread. The purpose of this article is to improve the design and electrical parameters of the resonator on open- and short-circuited stubs.

1 Conventional resonator on open- and short-circuited stubs. Features of the open-circuit stub equivalent capacitance and the transmission response (TR) of the resonator on open- and short-circuit stubs are considered. The equivalent capacitance frequency dependence leads to significant capacitance increasing at resonance. As a result, a high quality factor is achieved. However, such capacitance corresponds to a small inductance and, accordingly, unacceptably small length of the short-circuited stub. The disadvantage of the conventional resonator is also the low value of the stub characteristic impedance.

2 Resonator with increased length of short-circuited stub. In the article it is proposed two design decisions to overcome these disadvantages. It is shown that in contrast to the conventional decision with the same stub impedances, in the case of different impedance stubs — high-impedance open- and low-impedance short-circuited — the short-circuited stub is noticeably longer. The TR of two variants — 1 and 2 — resonator on different impedance stubs is given. The variants differ in the stub characteristic impedances values: variant 1 satisfy values for two-dimensional microstrip elements, and variant 2 — three-dimensional. The variant 2 has longer short-circuited stub and higher signal suppression in the suppression bands. Compared to the conventional decision, the length of the short-circuited stub in the variants 1 and 2 is 2.2 and 3.2 times longer. 

3 Resonator with transmission line section. The second of the proposed decisions is the introduction into the resonator design the section of main transmission line. It is shown that in the case of a high-impedance section the resonator quality factor increases. The resonator TR with quarter wavelength and half wavelength sections, which increase the quality factor by 3 and 4 times, is compared with the case without sections.

4 Results discussion. The proposed decisions make it possible to overcome disadvantages of the conventional resonator. The resonator based on these decisions has a length and width of λ0/4 (λ0 — resonant wavelength), the length of the short-circuited stub of λ0/16 (in the conventional design — λ0/43).

Resonator characteristics are improved in the case of range extension of the stubs characteristic impedances. For microstrip resonator design a significant impedances range extension is provided by three-dimensional elements.

Conclusion. The proposed decisions make it possible to improve the design and electrical parameters of the resonator on open and short-circuited stubs by increasing the length of the short-circuited stub, stubs characteristic impedances and quality factor. The obtained quality factor formulas allow defining the resonator design parameters in the first approximation.



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How to Cite

Нелін , Є. А. and Непочатих, Ю. В. (2022) “Improving Parameters of Resonator on Open- and Short-Circuited Stubs”, Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, (89), pp. 48-53. Available at: (Accessed: 24April2024).



Functional Electronics. Micro- and Nanoelectronic Technology

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