I.V. Zabegaylo1, A.I. Tyumentsev2, T.S. Timoshenko3, A.N. Yakovlev4

1–4 Omsk Scientific-research Institute of Instrument Engineering (Omsk, Russia)

1–4 107@oniip.ru

Problem statement. Switchable and tunable LC filters are used as frequency-selective devices in radio engineering equip-ment for various purposes. Due to the great potential for minimizing the weight and size of tunable filters compared to switchable ones, tunable filters are most widely used in modern receiving and transmitting equipment. At present, much at-tention is paid to the issues of designing tunable LC filters and improving their main technical characteristics. However, issues related to the study of their tuning range and its expansion have not yet received due attention. At the same time, an increase in the tuning range of frequency band LC filters makes it possible to further miniaturize frequency selection devic-es and improve the weight and size characteristics of electronic equipment.
Objective. Study of the possibility of extending the frequency tuning range of a bandpass LC filter based on a parallel os-cillator circuit with inductive coupling.
Results. The paper obtained relationships for calculating the values of the elements of a T-shaped bandpass LC filter con-sisting of coupling inductances and a parallel oscillatory circuit. Using the matrix of generalized parameters, the tuning range was estimated. It has been established that the tuning range of such a filter in frequency when using ideal elements in its composition, i.e. not taking into account losses and natural resonance, is limited only by the physical feasibility of the element values. The influence of the inductor coil parameters on the tuning range was studied. It was found that the greatest influence on the tuning range is the resistance of the loss of the contour inductance coil and the self-capacitance of the coupling coils. Recommendations are given for increasing the tuning range of the considered LC bandpass filter circuit.
Practical significance. The obtained results allow to implement tunable LC-filters with an extended tuning range in frequen-cy. Recommendations are presented that allow to extended the tuning range.
 

Zabegaylo I.V., Tyumentsev A.I., Timoshenko T.S., Yakovlev A.N. Study of the tuning range of LC filter on a parallel circuit with inductive coupling. Radiotekhnika. 2026. V. 90. № 4. P. 105−114. DOI: https://doi.org/10.18127/j00338486-202604-13 (In Russian)

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