Telecommunications and Radio Engineering, 59(1&2)

Yu.F. Logvinov
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Sea Surface Statistics in the Case of Radio Wave Backscattering at Low Grazing Angles

Computer simulation has been used to analyze statistical distributions of the heights, lengths, slopes and radii of curvature of illuminated surface patches, as applied to the case of backscatter at low grazing angles.

V.A. Komyak and S.A. Shilo
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St.,61085 Kharkov, Ukraine
Effect of a Rough Sea Anisotropy on Angular Dependences of the Ocean Microwave Radiation

Experimental results of the azimuth anisotropy measurements for the radio brightness of rough sea-surface are under discussion here. A statistically valid model of the sea surface has been proposed as a set of dual-slope prisms, orthogonal oriented to the surface wind direction. The conformity of results with other models and the adequacy of dependencies for wind contribution to the brightness temperature been estimated on the basis of this model and experimentally obtained, have been noted in this work. Sea wind-roughness peculiarities responsible for the behavior of angular dependencies of the azimuth anisotropy of radio brightness contrasts are interpreted here.

A.A. Kirilenko, D.Y. Kulik, and V.I. Tkachenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
General Scheme of the Mode-Matching Technique as a Basis for Generalized Solutions to the Internal Boundary-Value Problems

Our study is focused on a new generalized approach to the mode-matching (GMM) applied to the computation of the natural mode bases for the waveguides (WG) of complicated cross-sections and of the S-matrices of the complicated waveguide circuits. Development of the GMM procedures enables one to create fully automatic algorithms for a wide range of configurations avoiding a specialized analytical treatment of each new boundary-value problem. Moreover, the background for linking up the interface tools of a circuit geometry specification and editing is provided by the GMM approach together with the special algorithms for recognizing the object configurations and for data preparation. The class of objects that can be computed by the suggested approach includes arbitrary WG circuits with stepped metal boundaries specified in the Cartesian coordinate system or with the smooth boundaries that may be approximated by the equivalent staircase surfaces. The corresponding electromagnetic solvers are closer to the software based on the mesh methods, with the high accuracy and computation speed typical for sophisticated mode-matching procedures.

S. F. Kulishenko, A. A. Kirilenko, and S.L. Senkevich
Usikov Institute of Radio Physics and Electronics National Academy of Sciences of Ukraine
12. Academician Proscura St.. Kharkov 61085. Ukraine
Waveguide Bend Matched by the Stepped Miter

The 2D problem of the stepped mitered waveguide bend is considered for both E and H polarizations of incident waves. The method used here for analysis is the mode-matched technique. Geometric parameters of such a device that can provide the low level of the return loss within the whole operating frequency band are found for WR90.

V.A. Doroshenko and E.K. Semenova
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Field Behaviour Near the Vertex of a Cone with Longitudinal Slots

V.S. Miroshnichenko and Ye.B. Senkevich
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Experimental Determination of Equivalent Circuit Parameters of an Open Resonator Coupled to Transmission Lines

The techniques for determining the equivalent parameters of open radiation-losses resonator in a coupling a element are discussed. This method is based upon the approximation by the fractionally-linear functions of the measurement data on the total reflection factor at 3 points near the resonant frequency. This method has been experimentally tested for several types of coupling elements at the 8-mm wavelength. The behavior of the coupling elements' radiation losses near the resonant frequency and the excitation and energy output efficiencies of the open resonator have been defined.

Z.E. Eremenko and E.M. Ganapolskii
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Hemispherical Cavity Resonator for Measuring of Permittivity of Strongly Absorbing Liquid in Small Volume

New method is proposed for measuring microwave permittivity of strongly absorbing liquids in small volume. The method is based on use of hemispherical resonator with small spherical cavity filled with liquid to be measured. Characteristic equation for electromagnetic oscillations in this resonator is obtained and analyzed. Optimal dimensions of measuring cell and working mode of oscillations are found. It is shown that effect of displacement of electromagnetic field from cavity arises in such a resonator whose cavity is filled with liquid having large values of real and imaginary parts of permittivity,. Method is experimentally realized in 3 cm wave range. Theoretically predicted field displacement effect is revealed. Algorithm is found of determining of complex permittivity of liquid from measured values of Q-factor and resonant frequency shift.

M.A. Kopot, A.N. Nikitenko, and G.I. Churyumov
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
Investigations into the Dispersion Characteristics of the Electrodynamic Systems with Resonators of Complex Shape

One of the most important issues that evokes considerable interest of experts involved in microwave electronics and electrodynamics applications is designing and development of M-type tube resonant systems. An approach to considering the slow-wave (SW) structures of ordinary and converted arrangements with intricate-shape resonators and the computational results concerning the resonators' dispersion characteristics are given.

V.B. Baiburin, A.V. Sysuev, V.A. Sysuev, and A.A.Terentiev
Saratov State Technical University, Russia
Interaction of Axial and Cyclotron Electronic Oscillations in M-Type Devices

Based on the solution of the electron motion equations in the crossed electric and magnetic fields typical for magnetron devices (MD), a mechanism for setting up electronic oscillations along the axial direction of the device is considered. The interaction between these oscillations and the cyclotron motion of electrons are also shown. In terms of the phenomenon described above a mechanism is suggested whereby the high-energy electrons are capable of creating the anode current in the MDs, the afore-mentioned electrons lying outside the MD critical mode.

Vasyanovich A.V., Gritsunov A.V., Nikitenko A.N., and Horunzhii M.O.
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
General Principles of Spectral Modeling of Microwave Devices

G.P. Ermak, V.P. Kochergin, and P.V. Kupriyanov ^*
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
^*SPC “Istok”, Fryazino, Moscow region, 141120, Russia
Millimeter-Wave Planar Frequency Multiplier

The results of experimental study of the millimeter-wave planar frequency multiplier based on the varistor with Schottky-barrier are presented. The planar multiplier circuit designed on a teflon support was built into the slit of the waveguide unit containing the input and output waveguide lines of standard section. All the circuit components including the coplanar slot junctions, microstrips and slotlines were fabricated using the photolithography technique. The multiplier test-unit is capable of ensuring the input and output frequency bands of 47-58 GHz and 94-116 GHz, respectively. The maximum output power was 600 W with the input power being 20 mW.

V.M. Kuzmichov and S.V. Pogorelov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Improving the Accuracy of Temperature Dependence Measurements for the Absorption Efficiency Factor in Platinum Bolometers

The initial absorption efficiency factor of the platinum thin-wire bolometer and its relative standard deviation have been calculated in dependence on relative standard deviations of the bolometer diameter, radiation wavelength and specific conductivity. The temperature dependence of the absorption efficiency factor is represented by a second-order polynomial, using the least-squares fit to determine only two coefficients. The error of representing this dependence has been reduced essentially.

N.N. Beletskii and S.A. Borisenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
The Spectrum of Nonlinear Surface Polaritons in Semimagnetic Semiconductors in an External Static Magnetic Field

The influence of an external static magnetic field on the spectrum of nonlinear surface polaritons (NSPs) in semimagnetic semiconductors being in a phase of antiferromagnetic ordering has been investigated. It has been shown that in the external static magnetic field the NSPs possess the property of nonreciprocal propagation. The influence of the electron plasma frequency on the dispersion properties of the NSPs with monotonic and non-monotonic decaying electromagnetic fields from the boundary of the semimagnetic semiconductors has been determined.

U.R. Liyepin' and O.N.Stavitsky
Kharkov Military University
Algorithmic Reconstruction of the Radiation-Pattern Characteristics of a Partially Unexcited Antenna Array

A new technique for the algorithmic restoration of basic antenna pattern (AP) parameters has been analyzed and developed when part of array radiators experiences the “nonexcitation”-type failures under the operating conditions. One of the possible ways to implement the method which is adaptive to the failures of the amplitude-phase distribution (APD) synthesis radiators is presented. The above method calls for the zero forced formation of the AP faulty array in the directions corresponding to the nominal AP of the healthy array.

V.V. Ovsyanikov and Ye.D. Romanenko
Dnepropetrovsk National University
Radiation Characteristics of Circularly Polarized Dipole Antenna Arrays

Investigation results on the radiation characteristics of circularly polarized dipole antenna arrays are presented. The numerical calculations of the radiation pattern and the axial ration are exemplified for a 12-radial antenna array whose elements are fed with a periodically progressive phase shift and which is placed above a conducting screen. It is shown that the azimuthal radiation characteristics in the plane normal to the array axis are isotropic.

V.A. Katrich and M.V. Nesterenko
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
The Near-Zone Field and Resonant Frequencies of Narrow Longitudinal Slots in the Broad Face of a Rectangular Waveguide

Power frequency characteristics of the longitudinal slots are presented. It is shown that as the slot length increases the number of resonances increases as well.

O.V. Sytnik, Ye.I. Myroshnychenko, and Yu.А. Kopylov

Estimation of Implementation Errors Effect on Characteristics of Pseudorandom Radar Signal

Optimization of signal characteristics is considered in the radar systems with continuous radiation and pseudorandom phase modulation. Highly noisy conditions, in which such systems operate, determine the requirements that should be met by the signals being studied. The presence of the multiplicative noise makes it difficult to design optimal algorithms of echo-signal processing. The use of signals with a wide base and a complex modulation type demands elaboration of the equipment that will ensure precision accuracy of the signal generating and processing. The investigation of errors introduced into the signal in the generating stage and their influence on the resultant characteristics of the system as a whole has shown a possibility to achieve trade-off variants of the equipment construction. Error classification is given. An effective means for the construction of the maximum allowable error surfaces is proposed.

A.V. Sokolov and V.V. Lukin
National Aerospace University (Kharkov Aviation Institute),
17, Chkalov St., Kharkov, 61070, Ukraine
Local Recognition of Radar Images by Three-Layer Neural Network Using Spatial Features

Methods for increase in reliability of primary local recognition of radar images by a three-layer neural network are offered. Methods of neural network training are considered. The efficiency of the proposed neural network application is demonstrated by test data.

V.A. Pismenetski, N.I. Sliptchenko, and P.I. Platonov
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
The Dispersion-Spectral Method for Identification of Pulsed Radio Signals

The dispersion-spectral method is analyzed for identification of single radio impulses. The instantaneous value of the central frequency, the spectrum envelope widths at a certain level and the bandwidth ratio of this envelope are suggested here as descriptive features. The identification algorithm and the apparatus structure for its realization are suggested on the basis of the Bayes criterion.