A.V. Gribovsky and S.L. Prosvirnin
Institute of Radio Astronomy, National Academy of Sciences of Ukraine
4, Krasnoznamennaya Str., Kharkiv 61002, Ukraine
Frequency-Sensitive Characteristics of a Screen Having Rectangular Apertures and Waveguide Loads
The paper is devoted to a numerical analysis of frequency characteristic of a two-periodical perfectly conducting two-element screen of a finite thickness consisting of rectangular waveguide pieces. One of the waveguides is shorted, playing a part of a waveguide load. It was demonstrated that a screen whit a p-i-n diode connected in to a shorted waveguide can either fully reflect or fully transmit electromagnetic energy at the same frequency.
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A.S. Bryukhovetski1, A.S. Kashcheyev2, S.B. Kashcheyev2,
and Yu.Ì. Yampolski
1A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
2Institute of Radio Astronomy,
National Academy of Sciences of Ukraine
4, Krasnoznamennaya Str., Kharkiv 61002, Ukraine
Two-Position HF Scattering from the Rough Sea Surface. I. Theory
In the first part of the article the spectrum of electromagnetic waves scattered by the sea surface is theoretically investigated within the framework of the first order of the perturbation theory. The event of a linear omnidirectional antenna located near the sea surface which is illuminated by the incident field is considered. The finite conductivity of the sea-water, the sliding propagation of the scattered waves, the possible movement of the receiver and surface current are taken into account. The limiting passages to the known problem solutions have been performed.
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A.S. Kashcheyev1, S.B. Kashcheyev1, A.B. Koloskov1, I.I. Pikulik1,
A.S. Bryukhovetski2, and Yu.Ì. Yampolski1
1Institute of Radio Astronomy, National Academy of Sciences of Ukraine
4, Krasnoznamennaya Str., Kharkiv 61002, Ukraine
2A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Two-Position HF Scattering from the Rough Sea Surface. II. Experiment
In the second part of the article the measuring procedure is described and the investigation results of radio signals of HF broadcasting stations reflected from the ionosphere and scattered by the rough sea surface are presented. The experiments have been performed during the sea part of 7-th Ukrainian Antarctic expedition accomplished aboard the scientific-research ship “Gorizont”. The comparison of experimental scattering spectra with the model scattering, calculated in accordance with the theory developed in the first part of this paper, has been performed. The qualitative coincidence of the theory and the experiment has been shown. The possible physical reasons, responsible for the peculiarities of spectral structure of the signals have been investigated.
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G.P. Kulemin, V.A. Kirichenko, and Yu.F. Logvinov
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Temporal Variability of Centimeter-
and Millimeter-Wave Soil Back-Scattering
Experimental normalized radar scattering cross sections (RCS) of a bare-ground plot at an angle of incidence of 600 are presented. During the experiments roughness of soil and its moisture content varied, these parameters being monitored by contact methods. It is shown that when a radio signal is scattered by a surface, the predominant factor is the surface scattering mechanism.
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G.I. Sidorov, V.A. Tikhonov, I.V. Savchenko, and K.V. Netrebenko
Kharkov National University of Radio Engineering and Electronics,
14, Lenin Ave, Kharkiv, 61166, Ukraine
Equalization of Amplitude-Frequency Characteristic of a Channel of Communication in the Presence of Powerful Gaussian Noise
The intersymbol interference linear equalizer noise-resistant synthesis method is offered. This method is based on the use of statistics of the third order and in comparison with the traditional methods using statistics of the second order it ensures more exact synthesis of equalizer at the presence of the Gaussian noise. The offered method is similar to the method of reduction to zero of non-significant factors, but in this case it makes it possible to receive an equalizer for a high level intersymbol interference on the receiver input.
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À.N. Êuleshov, À.G. Pivovarova, and B.P. Yefimov
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
On Possible Mechanism of Spontaneous Radiation from Non-Relativistic Free Electron Beam in the Motz Undulator
Results of experimental research related to focusing and transport of electron beam with small kinetic energy value via the Motz undulator are given in this paper. It is demonstrated that application of external driving magnetic field improves the conditions for beam insertion into the system and exerts influence on spontaneous radiation intensity. Resonance scattering of space charge waves on periodical heterogeneities of undulator magnetic field was obtained in a large current density mode. The issue of possible influence of the Cherenkov radiation mechanism upon undulator system resonance radiation was discussed.
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Luis Nino-de-Rivera y Oyarzabal, Alejandra Alcala D, Miguel Cruz Irisson, and V.I. Ponomaryov
National Polytechnic Institute of Mexico
A Biocompatible PMMA Encapsulated Vision Prosthesis Case for Silicon Retina
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Î.I. Êîvalenko, F.V. Êivva, S.V. Êàlinichenko1, and L.À. Sukach
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
1 I. Mechnikov IMR AMS of Ukraine, Kharkiv, Ukraine
Some Characteristics of the Influence of Microwave Electromagnetic Radiation upon Vegetation Seeds and Germs
During 2000 to 2003 the theoretical and experimental investigations of the influence of electromagnetic radiation (EMR) of super-high and ultra-high frequency bands upon seeds of barley, sunflower, radish and cultures of coryneformic bacteria: C.d.gravis tox +, C.d.gravis small tox +, C.d.mitis tox +, C.d.belfanti tox +, C.ulcerans tox + were carried out. Before the irradiation the objects had been prepared and treated in compliance with the government standards (GOSTs) and recommended methodology. In the microwave band the radiation was executed at the frequency of
f0 = 2450 ± 50MHz with average power Paver = 102-103W (pulse power Pp = 1 kW, on-off pulse ratio n = T/Tp = 1-10. In K and Q band there were used standard generators G4-141 and G4-142 operating within the discrete frequency bandwidths f = 37.5-78.33GHz and at the average power of Pa = 1-5 mW. There are demonstrated the distinctions in biological processes during their heating in the microwave field and in the thermostat as well as the possibility of modification of the biological activity of vegetation seeds and germ cultures applying the low-intensity EMR within the discrete bandwidths of UHF-band. Special attention should be paid to repairing of the sprouting energy of the seeds that were primarily inhibited by thermal action.
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