Radio physics and electronics

3-8

Authors: Hе Shi, N.G. Kokodiy, M.V. Kaydash, S.N. Shulga, S.V. Pogorelov

Subject and Purpose. In laser measurements technique, the absorption and scattering of microwave radiation in a wire, which diameter is much smaller than the wavelength, can be very large. The absorption and scattering efficiency factors can reach values of several hundreds. This effect has been investigated under the conditions when a plane wave falls on a wire in free space and the electric vector of the wave is parallel to the wire axis. The effect also appears if the wire is located along the axis of the radiation beam, but in this case the absorption in thin wires is appeared to be less. In thicker wires, it may be large. This paper shows that such an effect exists when a thin wire is located along the axis of the beam propagating in a hollow metallic waveguide. Methods and methodology. An experimental study of the effect of strong interaction of microwave radiation with very thin (d << l) metal wires located along the axis of a hollow metal waveguide was carried out. The transmittance and reflection coefficients of the waveguide section with a wire in the frequency range from 12 to 18 GHz were measured. The absorption and scattering coefficients of the wires are evaluated. The diameters of the wires ranged from 50 to 1000 microns, while their length ranged from 100 to 200 mm. The waveguide cross-section is 8 ´ 16 mm, the wave type is H10. Results. Our experiments have shown that the transmittance values of the section with the fiber are in the range of 80…90 %; the reflectance values are in the range 1…5 %, depending on the fiber length and its diameter. At some frequencies, where resonances are observed, the transmittance reduces down to 10…20 %, and the reflectance increases up to 10…40 %. Conclusions. The results of our study have showed the existence of the effect of strong interaction of microwave radiation with very thin conductive fibers in the waveguide with a longitudinal fiber arrangement. The effect can be used in the development of waveguide elements for measuring equipment: attenuators, absorbing loads, etc.

21-29

Authors: A.P. Nickolaenko, Yu.P. Galuk, M. Hayakawa

Objective and purpose of the work. We model disturbances in amplitude spectra of vertical electric and horizontal magnetic field components of the signals of global electromagnetic (Schumann) resonance by a seismogenic non-uniformity of the middle atmosphere. The point field source is used positioned at S-E Asia, Africa, or S. America. Observer is found at the Moshiri observatory in Japan (44.37 N, 142.24 E.) and the earthquake modifying the middle atmosphere is situated at Taiwan (21.82 N; 120.81 E). Disturbances are computed in amplitude Schumann resonance spectra and their similarity is demonstrated to observational data. Methods and methodology of work. The propagation parameters of extremely low frequency (ELF) radio waves are found by using the full wave solution in form of Riccati equation. The spectral components of fields are found numerically be using the two dimension telegraph equations having the parameters of regular and non-uniform Earth – ionosphere cavity. Results. We obtain numerical estimates for an impact of localized seismogenic non-uniformity on amplitude spectra of electric and magnetic fields in the frequency band of global electromagnetic (Schumann) resonance. Similarity is demonstrated between the model and observational spectra. Conclusion. The model suggested for a seismogenic non-uniformity in the moddle atmosphere allows to successfully interpret the observations ELF data.

45-60

Authors: M.V. Mil’cho

Subject and purpose. Presently, there is a problem of creation of simple in exploitation generators for a sub-millimeter range, especially in his shot-wave part. Electro-vacuum generators of type BWT and klynotron are work out for long wave part of sub-millimeter range. Difficulties at designing are increase with shortening of wave length. The sizes of the slow-wave structures diminish, requirement to the density of current of electronic bunches and to quality of their focusing, increase. The use electro-vacuum multipliers of frequency, can weaken these requirements considerably. The numeral research of the catcher for the electro-vacuum frequency multiplier, is described in this paper for sub millimeter range. The aim of these researches are an estimation of attainable output power of frequency multipliers and search of optimal parameters for their realization in sub-millimeter range of waves. Methods and methodology. For a calculation catcher efficiency, the analysis of three-dimension motion of electronic bunch in set field of the slowing wave system is conducted. For the numeral integration of the electron motion equation, the universal program “KLYNOTRON” is used. This program was worked out by us before for BWT and klynotron research. In this program many parameters of the real task are take into account. For description of spatial distribution longitudinal and transversal constituents of electric-field tension, the exact analytical method of conformal mapping is used. Thus, all spatial harmonics of the field are taken into account at once in analytical expressions and the field singularity is exactly described near-by the ribs of metallic elements. Results. A numeral study of catcher parameter influence is undertaken on the output power of multiplier. On the ranges of waves 0,5 mm and 0,3 mm the regime and possible for realization catcher structural parameters are certain Conclusions. Undertaken a study showed that at existent technological possibilities really to create the multipliers of frequency in the range of waves at 0.3…0.5 mm with output power at order ten millwatt. A necessary condition for creation of such devices is optimization of parameters of buncher of electronic clots in the multiplier of frequency.

67-82

Authors: V.V. Ovsyanikov, D.M. Svinarenko, E.R. Beznosova, L.Z. Tsypko

The subject and purpose of the work. The methods and results of calculations of the electrical characteristics of the wire randomly bent antennas of the microwave range have been investigated with the purpose of significantly expanding their capabilities and increasing the accuracy of the electrical parameters computations. Methods and methodology of work. The methods and methodology of studies of arbitrarily curved wire whip and loop antennas are considered with concentrated arbitrary loads and excitation nodes included at arbitrary points. An approximate calculation of such antennas is performed by the method of an equivalent long line, and rigorous calculation by the integral equation method with respect to the distribution of the complex current on the antenna. Results of the work. The algorithm of step-by-step development of randomly bent wire whip and loop antennas with arbitrary concentrated loads and excitation nodes included at arbitrary points is proposed. A comparative analysis of the possibilities and errors in calculating approximate and rigorous methods for calculating similar antennas is performed. Аn approximate methods are quite useful for preliminary estimation of input parameters of antennas, and also as an initial approximation for the parametric synthesis of a developed antenna or antenna system. If the accuracy of calculating the antenna parameters by an approximate method is insufficient, it is recommended to apply a rigorous method – the integral equation. The singularities of solving integral equations with respect to the distribution of complex current on linear arbitrarily curved thin pin and loop antennas composed of rectilinear segments of conductors with an arbitrary number of concentrated complex loads and excitation nodes are studied. It is shown that the application of Fredholm integral equations of the first kind to the analysis of such antennas with allowance for the Pocklington integral equation makes it possible to expand the variety of variants of their configuration. However, such integral equations, as is well known, do not satisfy the condition for the correctness of the solution. This negative property leads to instability of the solution of the problem for the current by the integral equation method and to a decrease in the accuracy of calculation of the antenna parameters. To eliminate such a defect and to obtain a stable solution of the integral equation, a method is proposed for diagonalizing the matrix of the coefficients of the system of equations. To solve the problem of calculating such antennas, DISTRIBUTION software was proposed, with the help of which a number of calculations of various pin and loop bent antennas with loads were performed. Examples of calculation with the help of this computer program of the direct and inverse matrices of the system of algebraic equations are given and then the determination of the complex distribution of the current and the input resistance of the investigated antennas is given. The conclusion. The type of antennas under investigation is expanded and the accuracy of calculations of their parameters is increased. It was noted that for the first time in the world practice the method of the integral equation for the calculation of such antennas was proposed and published, which outstripped the development time, the methods and computer programs proposed subsequently. The results of the calculations are consistent with the literature data and experimental results. Based on the studies of antennas by the integral equation method, new designs were developed, some of which were introduced into production and operation when installed on space vehicles and other objects