V.A. Lyaschenko and V.A. Katrich
V. Karazin National University of Kharkov, 4, Svoboda Sq., Kharkov, 61077, Ukraine
External Admittances of Wide Slots

The external self- and transfer admittances of slot radiators are analyzed without limitations on the slot width. Sinusoidal (harmonic) functions are used as coordinate functions of the field distribution along the slot, while the field across the slot is assumed to be uniform. Electric length dependences of the slot self-admittance are represented graphically. It is shown that the admittance magnitude depends essentially on the slot width and length, as well as on the exciting field wavelength. The region of applicability is determined for approximate external admittances of the slot. The coupling between two, arbitrarily separated parallel slots is analyzed. It is shown that the existence of a strong coupling effect can be used to implement a required amplitude-and phase distribution of the field over the aperture of a multislot antenna, for example like the distribution providing a superdirectivity operation mode of an antenna.

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A.N. Dumin
V. Karazin National University of Kharkov, 4, Svoboda Sq., Kharkov, 61077, Ukraine
Power Characteristics of Non-Stationary Radiation from the Open End of a Coaxial Waveguide

The "modal basis" technique is used to analyze the radiation of a non-stationary wave from the open end of a coaxial waveguide. Analytical expressions have been obtained for the fields radiated into free space from a waveguide excited by a TEM-mode with a step-like waveform. The case of an arbitrary waveform has been analyzed numerically through computation of the Duhamel integral. Power characteristics of the radiated field are analyzed.

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I.N. Bondarenko
Kharkov Military University, 6, Svoboda Sq., Kharkov, Ukraine
Dominant Factors Restricting Limit Values of Electromagnetic Fields in Superconducting Resonators

This article considers the limitations imposed on the electromagnetic field values in the low-temperature superconducting resonators (SCR) by such effects as magnetic, thermo-magnetic, and thermal breakdown, HF gas discharge, autoelectronic emission, electron resonance discharge, and so on. Numerical estimation of the influence of the restricting factors is given. On the basis of the analysis carried out the requirements for manufacturing methods, designs, and service conditions of SCR are determined.

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V.M. Onufrienko
Zaporizhya State Technical University,
64, Zhukovskaya St., Zaporizhya, 69063, Ukraine
 The Differintegral Model for Describing Fractal Coupling Between Waveguide Surfaces

The integrodifferential power characteristics of the electromagnetic (EM) field are utilized to describe fractal coupling between waveguide surfaces. A study has been made of the fractal coupling mode in the "dielectric waveguide-diffraction grating" system. It was ascertained that the energy dissipation recording on a rectangular grating edge can well be made possible. The calculated characteristics of a differintegral model of the system are in good agreement with the findings of experimental investigations.

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K.A. Vytovtov
Dnepropetrovsk State University
Analysis of Stop-Band Boundaries for Harmonic Waves in a Periodic Layered Bianisotropic Medium

Stop-bands for a harmonic wave are analyzed in a periodic layered structure with a uniaxial bianisotropy. An analytical approach, based on the per-period transformation matrix is used. Expressions to determine the boundaries to the instability domain are derived and analyzed.

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L.A. Titarenko
Kharkov State Technical University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
 Consideration of Antenna Elements Mutual Influence on Efficiency of Adaptive Spatial Signal Processing

The mutual influence of antenna elements essentially decline of adaptive spatial signal processing signal/(interference+noise ratio). The G-robust algorithms are offered and investigated for lowering a negative effect coupling antenna elements.

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Yu.A. Koval and O.L. Troshchin
Kharkov State Technical University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
 Analysis of Time and Frequency Standards Synchronization Algorithms

The general model of synchronization systems is suggested for various algorithms of temporal information transfer. The basis for model is a synchronization system error. The relations for estimation of the synchronization errors are presented for the modern high precise systems.

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I.M. Mytsenko and S.I. Khomenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
 Coverage Range of Shipborne Centimeter Wave Navigation Radars: Regional Experimental Studies in the World Ocean

Results of measuring the coverage range of a centimeter wave shipborne radar are presented. The effects of wave propagation conditions and of the radar performance figure are analyzed. Coverage range distribution functions are presented for each of the regions investigated.

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V.M. Kartashov
Kharkov State Technical University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
 On the Increase in Accuracy of Meteorological Values Measurement in Acoustic and Radio Acoustic Atmosphere Sounding

Methodical errors in evaluation the wind velocity under acoustic sounding of atmosphere have revelated. The error estimating and more refined formulae for wind velocity calculation have been obtained. A new algorithm of signal processing for combined sodar-radar system was offered; it allows to increase precision of temperature and wind velocity.

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O.V. Botsula, V.V. Medvedev, and E.D. Prokhorov
V. Karazin National University of Kharkov, 4, Svoboda Sq., Kharkov, 61077, Ukraine
Application of Resonance-Tunnel Diodes for Frequency Multiplication at Millimeter Wavelengths

Discussed in the paper is frequency multiplication in resonance-tunnel diodes with a variety of current-voltage characteristics. Single-level resonance-tunneling diodes like Al0.2Ga0.8As/GaAs, In0.53Ga0.47As/AlAs, InAs/AlAs/GaSb and the two-level AlAs/GaAs are considered. As has been found, the highest frequency conversion factors at all harmonics are shown by the two-level resonance-tunneling diode, with or without bias voltage, compared with the single level resonance-tunneling diodes. The high frequency conversion factor for the harmonic components enables obtaining power levels at the harmonics comparable to those of Gunn generators and avalanche-transit time diodes at millimeter wavelengths.

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A.B. Gourinivich, V.D. Yeryomka*, A.A. Kuraev, and A.K. Sinitsyn
Belorus State University of Computer Science and radio Electronics,
6, P.Brovka St., Minsk, 220027, Belorus
*A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Theory of Relativistic O-Type TWT Based on the Irregular Waveguide

Self-consistent non-linear one dimensional equations of the relativistic linear beam TWT with slow-wave system in the form of arbitrary irregular waveguide are stated in terms of account the arbitrary number of harmonics of signal and average forces of electron interaction. By applying the general theory, two versions of the optimized O-type TWT have been investigated including a variation with optimized profile of waveguide and 85% efficiency. The influence of second harmonic of signal is estimated for efficiency-optimized TWT. The frequency band characteristics thereof are investigated.

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I.A. Vyazmitinov, I.V. Lopatin, and A.S. Tishchenko
A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
 Modified Helmholtz Coils

It is shown that the varying of the configuration of the end faces of the Helmholtz coils from planar configuration to ellipsoidal configuration leads to an increase in magnetic field induction and in the uniformity level of the field in the working gap of the system. A modification is suggested of the thread-like currents technique for the calculation of magnetic fields. The analysis is carried out of the fields structure in various versions of the Helmholtz coils.

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A.L.Nefedova, I.D. Sakhatsky, B.Al-Tahhan, and A. Al-Heari
Kharkov State Technical University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
 Investigation of Electromagnetic Field Distribution in a Production Area Containing a Radiation Source

The method for defining the electromagnetic field distribution in the production area with radiation source is offered. The influence of the wall parameter on the dangerous radiation zone configuration is investigated.

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A.M. Rybalko, S.V. Sevsky, and V.M. Shokalo
Kharkov State Technical University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkov, 61166, Ukraine
 Efficiency of Energy Transmission with Microwave Beam under Parabolic Amplitude Distribution of the Exited Field

The conventional optimization problem of the beamed microwave energy transmission system is considered. The criterion of maximum efficiency of power intercept is parabolic function of distribution on the transmitting antenna. It is shown that under such a condition of amplitude distribution becomes more uniform than as the unconditional optimization. In this case, we can substantially increase the power radiated by the transmitting antenna losing the power intercept no more than 2%.

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