A.V. Vorobiev – Engineer, 

NIKA-Microwave, Ltd (Saratov)

E-mail: alexvorxx@mail.ru

B.M. Kats – Ph.D.(Eng.), Head of Department, 

NIKA-Microwave, Ltd (Saratov)

E-mail: brs19520@yandex.ru

A.I. Korchagin – Ph. D. (Eng.), Leading Research Scientist, 

NIKA-Microwave, Ltd (Saratov)

E-mail: korchagin_aleksey@mail.ru

A.Y. Kuptsov – Leading Design Engineer, 

NIKA-Microwave, Ltd (Saratov)

K.A. Sayapin – Engineer, 

NIKA-Microwave, Ltd (Saratov)

E-mail: sayapin.k.a@mail.ru

Waveguide band-pass filters (BPF) used in space and terrestrial communication systems must remain operable in conditions of low and high temperature. Waveguide BPFs made without taking additional actions experience temperature drift of parameters (center frequency, VSWR and insertion losses), associated with a change in the geometric dimensions of the resonators and coupling elements. In the development of BPF, the prediction of the temperature drift of parameters becomes an important task. As an example, this article investigated the temperature drift of the parameters of the X-band waveguide BPF with two-mode cylindrical cavity resonators. The synthesis of the X-band waveguide channel BPF with two-mode cylindrical cavity resonators is briefly considered. As a result of the synthesis, the optimal geometry of the BPF was obtained, the analysis of the three-dimensional electrodynamic BPF model was performed. An analysis of temperature drift of the filter model is considered using one of the packages of numerical multiphysical modeling. For this purpose, a mechanical model of BPF was created, containing 11 parts rigidly connected to each other from materials with different physical properties. Initially, temperature modeling of the BPF was carried out in a stationary thermal mode. For this, a stationary temperature solver based on the finite element method was used, integrated into the package of numerical multiphysical modeling. Then, modeling of elastic mechanical deformations of the BPF, caused by thermal stresses in the structure, was carried out. For this, a structural mechanical solver based on the finite element method was used, integrated into the package of numerical multiphysical modeling. The solution obtained in the temperature simulation served as the source of the deformations. After that, electrodynamic modeling of the BPF with the deformed geometry was performed. The simulation results at temperatures of −30°C, 20°C, 70°C made it possible to calculate the temperature coefficient of frequency. An experimental study of a prototype of the X-band waveguide BPF with two-mode cylindrical cavity resonators is presented. To set and maintain the temperature mode, the BPF under study was located in the chamber of cold, heat and humidity. S-parameters of the filter were measured using a vector network analyzer at −30°C, 20°C, 70°C. According to the measurements, the temperature coefficient of frequency was calculated. Comparison of the results of numerical simulation and experiment showed discrepancies associated with the fact that in the real design of the BPF the connections of the parts are not completely rigid.

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