Перегляд за Автор "Trubin, O. O."

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    Controlled Brewster effect in the scattering of electromagnetic waves on pseudo-rotating lattices of dielectric resonators
    (КПІ ім. Ігоря Сікорського, 2023) Trubin, O. O.
    Various conditions for the occurrence of anomalous scattering, in which most of the power is emitted by the lattice only in the direction of propagation of the incident wave, are analyzed. An analytical model for the scattering of plane electromagnetic waves on arrays of pseudo-rotating dielectric resonators (DRs) of cylindrical and rectangular shape is developed. New analytical relations are derived for the functions that determine the coupling between the field of a plane wave and the main types of magnetic oscillations of the rotated DR. The angles between the axis of the DR and the directions of propagation of plane waves, at which the coupling between the DR and the incident wave reaches extreme values, are studied. The conditions of non-resonant scattering and scattering with the absence of a reflected petal, known as the Brewster effect, were established. The general relations between the angles of inclination of DRs, polarization and the angles of incidence of waves on lattices, which lead to special cases of scattering, were found. There is a similarity between non-resonant scattering and the known Malyuzhynets effect, which describes the passage of waves through lattices of other types. Scattering models for lattices of rotated cylindrical and rectangular DRs were built. The difference between the classical Brewster effect and the petal-free cases of scattering on lattices built on the basis of the use of pseudo-rotating DRs was noted. In particular, it’s shown that, unlike other methods of realizing metasurfaces of this class, cases of scattering without petals on lattices of pseudorotating resonators are possible when the angles of incidence are changed in a wider band. The obtained theoretical results allow us to propose a new class of devices built on the basis of the use of pseudo-rotating DRs, to significantly reduce the calculation time and to optimize complex multi-resonator structures. New types of lattices built on pseudo-rotating DRs can be used to design a wide class of antennas, as well as multiplexing devices in terahertz, infrared, and optical wavelength range communication systems.
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    Scattering of Electromagnetic Waves by Frequency-Detuned Systems of Dielectric Resonators
    (КПІ ім. Ігоря Сікорського, 2024) Trubin, O. O.
    The general problem of scattering on a system of frequency-detuned coupled Dielectric Resonators (DRs) located in one or several transmission lines is considered. The field describing the natural oscillations of the system of detuned DRs is decomposed over the field of partial resonators. A system of equations is derived, the solution of which allows one to determine the frequencies and amplitudes of the system’s natural oscillations. It is shown that the resulting system of equations, by means of algebraic transformations, can be reduced to the problem of determining the eigenfunctions and eigenvalues of a finite-dimensional operator, determined through the elements of the coupling operator of frequency-detuned DRs. The limitations of the proposed calculation method are noted. The solution to the scattering problem is expanded in terms of the natural oscillation field of the system of detuned DRs. A system of linear equations for the amplitudes of forced oscillations is obtained. It is shown that in the particular case of identical resonator frequencies, the found system exactly coincides with the equations obtained previously for various types of DR. General solutions are found for the scattered field on frequency-detuned resonators located in different transmission lines. Several examples are given of calculating the frequency dependences of the scattering matrix for the most interesting structures consisting of coupled dielectric resonators detuned in natural oscillation frequencies. The frequency characteristics of the scattering of two bandstop filters with different stop bands, made on detuned DRs in the same transmission line, are calculated. The frequency dependences of the scattering matrix on two bandpass filters located parallel between regular lines are calculated. The scattering characteristics of bandpass filters of complex designs containing various DRs are calculated: a bandpass filter built on a system of coupled DRs in a transmission line break and several DRs in a regular line, as well as an elliptical bandpass filter. The capabilities of the proposed method are demonstrated by the example of optimizing the scattering characteristics of a demultiplexer built on the basis of two bandpass filters with different passband frequencies. The proposed method also makes it possible to calculate the scattering characteristics of bandpass and bandstop filters with several operating frequency bands used in modern communication systems.
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    Towards a New Implementation of Bandpass Filters on Basis of Band-Stop Structures on Dielectric WGM Microresonators
    (КПІ ім. Ігоря Сікорського, 2023) Grygorenko, O. G.; Trubin, O. O.
    A new method of constructing band-stop filters based on a system of optical microresonators with whispering gallery oscillations of ultra-high Quality factor (Q) is proposed, which are widely used in various integral filters of the optical wavelength range. To reduce the mutual coupling, the system of microresonators is located on different sides of the regular transmission line. With the help of perturbation theory, an electrodynamic model of filters was developed, which describes a complex system of interconnected microresonators with doubly degenerate types of natural oscillations. The obtained general analytical expressions are used to describe the characteristics of the scattering of natural waves of the line on the system of optical microresonators, which form a band-stop filter or an alternative band-pass filter. The frequency dependencies of the filter scattering matrix were calculated and analyzed. On the basis of the built analytical model, and using the periodicity of the microresonators’ own oscillations, with a change in the free spectral range (FSR) value, the possibility of constructing a new class of band-pass filters has been proven. The new filters differ from the known ones in that they simultaneously use two types of natural oscillations of adjacent microresonators. Amplitude-frequency characteristics of filters with different sizes of operating frequency bands are calculated. Based on the comparison of the obtained data, a conclusion about the reduced dependence of the losses of the proposed filters on the bandwidth is made. It is noted that the amplitude-frequency characteristics of the new class of filters are close to linear ones. The obtained practical simulation results allow significantly reducing the calculation time and optimizing complex multi-resonator structures for optical communication systems.