Radio physics and electronics

3-9

Authors: Yu.V. Svishchov

Subject and Purpose. The spectral characteristics (eigenfrequencies, eigenmodes, Q-factors) of a spherical particle with arbitrarily valued permittivity and permeability are considered to take a further look into some important features of their behavior. The real and imaginary parts of the material parameters of the particle can be both positive and negative. The emphasis is on magnetic type modes. Methods and Methodology. The spectral problem is solved using the electromagnetic field expansion in vector spherical wave functions. Results. The first eigenfrequencies of a spherical particle have been calculated depending on its relative permittivity e 1 and relative permeability m 1 whose real and imaginary parts can take both positive and negative values. The eigenmodes split into two, internal and external, eigenmode families. The internal eigenmodes bear an independent, associated with eigenmode structure labeling in each quadrant of the plane (m 1 , e 1). The external eigenmodes, on the contrary, have a uniform labeling throughout the whole (m 1 , e 1) plane and bear a structural resemblance to surface plasmon oscillations distributed in the vicinity of the particle surface or outside it. In the first quadrant of the plane (m 1 , e 1), the external eigenmodes repeatedly interact with the internal eigenmodes, leading to either mode hybridization or mode type exchange. In the third quadrant of the plane (m 1 , e 1), the external eigenmodes can interact with one another. The anomalous behavior of the spectral characteristics of a spherical particle corresponds to the already known phenomenon of wave mode coupling described in the scientific literature well enough. Conclusion. The performed study has revealed some new behavioral patterns as to the spectral characteristics of a spherical particle with arbitrarily valued permittivity and permeability

18-29

Authors: R.E. Pashchenko, V.K. Ivanov, D.O. Tsyupak

Subject and Purpose. Comparative analysis of the shapes of phase portraits of Doppler signals (DS) reflected from drone rotating rotors is given with regard to different time delays. The shapes of DS phase portraits are examined for various rotational velocities and numbers of the rotating rotors. Methods and Methodology. A method using phase portraits is suggested for analysis of Doppler signals reflected from drone rotating rotors. The method determines the number of the rotors and estimates their rotational velocities. Results. It has been found that the shape of the phase portrait of the baseline signal is practically independent of the time delay and can be described as an occasional movement of the image point following the phase trajectory in the center of the phase portrait. The appearance of characteristic regions on the periphery of the phase portrait allows separating baseline and sounding signals. It has been shown that the shape of the DS phase portrait of the rotating rotor during the flight movement of the drone depends on the time delay value. With a larger delay, phase portraits similar in shape appear at regular intervals equal to the Doppler signal period. With a larger rotational velocity of the rotor, the rate of similar phase portrait appearance diminishes. Conclusion. During the sounding of drone rotating rotors, the shapes of DS phase portraits depend on the value of time delay. With a larger number of rotors in the drone flight, the periodic change character as to the DS phase portrait shape remains unchanged. In this case, DS phase portrait shapes differ substantially for different numbers of drone rotors

38-53

Authors: M.V. Mil’cho, K. Ilyenko

Subject and Purpose. A special need for oscillators amenable to operation in the short-wave end of the submillimeter wave band sends us in search for new ways of their development. A proposal exists related to vacuum-tube frequency multipliers based on the backward-wave oscillator (BWO) or its variant, the clinotron. Sometimes a simultaneous excitation of two different-frequency oscillations is experimentally observed in ordinary millimeter wave clinotrons, orotrons and diffraction radiation oscillators. The aim of the present study is to examine whether those operational regimes can be implemented in the creation of electronic frequency multipliers in the submillimeter wave band. Methods and Methodology. The research method is a theoretical analysis of the process of simultaneous interaction of the electron beam with the electromagnetic fields of two modes in the BWO slow-wave structure. The aim is finding relationships to impose on the slow-wave structure parameters and the BWO operation figures and thus furnish a simultaneous excitation of the two modes. The obtained relationships are tested against published experimental results. Results. Two conditions of simultaneous mode excitations have been formulated, requiring (i) equal velocities of the operating spatial harmonics and (ii) their strict frequency multiplicity. Handy diagrams have been constructed, which made it possible to build frequency multiplication schemes with any multiplicity. The rigorous analytical method of comb dispersion calculation has been generalized to the higher passbands of large numbers. The calculation results have been compared with relevant experimental data, lending support to the validity of the obtained formulas to describe the frequency multiplication regime. Conclusion. A possibility has been theoretically shown of designing submillimeter vacuum-tube frequency multipliers upon clinotron-type oscillators with a single slow-wave structure. The regime of simultaneous generation of two given frequencies requires that the system dispersion in different passbands be controlled by moving a screen over the comb-type slow-wave structure.

66-79

Authors: A.O. Puzanov

Subject and Purpose. The present paper is concerned with the method of surface schooping of materials using high-frequency torch discharge (HFTD) and glycerol vapor as a base for dissolving activating additives to the working gas. To approach the problem, a steam generator is employed in an effort to improve the HFTD catalytic performance in the activation of surfaces and deposition of coatings on them. The purpose is to develop a design technique of a steam generator intended for making a proper gas environment in the HFTD burning area. The discussed design techniques seek to enhance efficiency of the self-contained steam generator with allowance for its small size compared to the wavelength. Methods and Methodology. The analysis of the glycerol vapor behavior in the HFTD plasma depends on the knowledge of glycerol molecule ionization potential in the electron impact case. To find out about the measure to which the glycerol vapor affects the HFTD current, a known calcium ionization potential is used as a defined point. The heating elements as part of the steam generator are designed in terms of thermal design methodology adopted in the electroheating machine making. The calculation formulas of the running time ratios of the steam generator with various heating elements and energy efficiencies have been obtained in terms of galvanic cell theory. Results. It has been shown that glycerol vapor itself cannot affect the HFTD current. For the HFTD excitation, the microwave region has been chosen. In cooperation with activating additives to the discharge plasma, this factor also adds to the HFTD current increase. Hence, the HFTD catalytic performance depends not only on the HFTD energy and its excitation field frequency but on the glycerol-dissolved additives as well. A special design has been developed for the heating element as part of a small-size steam generator. Reference tables have been composed, enabling one to pick up a prpoper diameter and number of parallel connected wires in the spiral coil. Conclusion. A good use of glycerol vapor as a base for vaporous fluxes and activating additives to the HFTD working gas has been shown. The developed design technique concerning the heating element of the steam generator optimizes its heating circuit. Specifically, it enhances the steam generation and reduces the power consumption of the steam generator running on the galvanic cell. Second, it makes it possible to use stainless-steel spiral heating coils in regime of automatic temperature control.