2009, volume 14, № 1
Т- AND Н-OSCILLATIONS IN WAVEGUIDE-COAXIAL RESONATOR
S. P. Martynyuk, A. P. Motornenko, I. G. Skuratovskiy, O. I. Hazov
7-10
T- and H-oscillations in the waveguide-coaxial
resonator (WCR) have been investigated. The numerical calculations of the
dependences of the T- and H-oscillations eigen frequencies and the H-oscillations eigen 
-factors on resonator parameters have
been carried out. The experimental investigations of the T- and H-oscillations have been carried out in integrated composite
model of the WCR. The calculated data go with experimental data.
MODELING OF PLANE ELECTROMAGNETIC WAVE SCATTERING BY A METALLIC CYLINDER
E. A. Velichko, A. P. Nickolaenko
11-18
The classic solution is used of the plane wave diffraction by a circular metallic cylinder. The spatial field distribution was constructed for four characteristic frequencies. The lower couple of them corresponds to the first maximum and minimum in the complete field observed at the back of the cylinder. Two higher frequencies around 100 GHz are related to the field maximum and minimum at the same point. Angular patterns of the scattered and full field are constructed. The phenomenon is discussed similar to the Gibbs phenomenon arising in the Fourier expansion of a «square» wave. In the 2D case, the effect vanishes when the number of terms in the expansion exceeds a threshold that depends on the relation between the radius of the scatterer and the incident wave length.
Quasi-optical ring sapphire rEsonator with cylindrical conductor inside
A. A. Barannik, K. I. Torokhtyi, N. T. Cherpak
19-23
In this paper a new approach to surface resistance Rs measurements of the volumetric conducting samples is investigated. The technique of determination Rs by means of the open quasi-optical ring dielectric resonator, in which “whispering gallery” modes are excited, is presented. The basic properties of the resonator are investigated experimentally and numerically in the frequency interval of 30–40 GHz. The possibility of high temperature superconductor Rs measurement by means of the ring dielectric resonator is displayed.
FORMATION OF THE QUASIUNIFORM OUTPUT RADIATION IN THE WAVEGUIDE METAL RECTANGULAR RESONATOR WITH a nonuniform mirror
A. V. Volodenko, O. V. Gurin, A. V. Degtyarev, V. A. Maslov, V. A. Svich, A. N. Topkov
24-27
The method of obtaining wave beams with a uniform intensity profile in the waveguide metal rectangular resonator is described. It is based on the self-imaging properties of multimode rectangular waveguides and using the nonuniform mirror with the discretely distributed absorbing or scattering sections. The theoretical model and calculation algorithm of characteristics of the low-loss Fourier-mode with uniform intensity distribution at the output mirror of the WQR are developed with application of the eigenmodes and the Fourier-optics methods. The conditions of Fourier-mode existence are established by changing the resonator geometry and its nonuniform mirror parameters.
SIMULATION OF MICROWAVE PROPAGATION IN EVAPORATION DUCT OVER ROUGH SEA SURFACE
Yu. V. Levadnyi, V. K. Ivanov, V. N. Shalyapin
28-34
Previous investigations of microwave propagation by the numerical split-step parabolic equation method used Kirchhoff approximation to take into account rough sea surface scattering. Those approaches ignored effects of self-shadowing sea surface and deviation of sea surface height probability distribution from a normal law. Methods for taking into account these effects are considered in the paper. Height and distance dependencies of propagation factor for microwaves in the presence of evaporation duct are calculated. It is shown that shadowing influences on microwave propagation in the evaporation duct are more significant than the effect of non-gausianity. Obtained results make it possible to improve accuracy of the microwave propagation forecast in the low troposphere.
MODELLING OF ELEVATION ANGLES MEASUREMENT OF LOW-ALTITUDE TARGETS BY MULTIFREQUENCY MONOPULSE RADAR
Yu. A. Pedenko
35-42
The computer simulation of measuring elevation angles of low-level targets has been carried out by means of three-frequency monopulse radar above the rough sea under multipath conditions. It is shown that the use of three-frequency monopulse radar substantially decreases errors of elevation angles measurement in comparison with single-frequency version. The use of three-frequency monopulse radar also reduces the possibility of tracking loss. The dependence of these characteristics on frequency spacing has been investigated.
PARAMETERS OF THE STRATIFIED METEOROLOGICAL FORMATIONS ABOVE THE Black SEA
V. A. Kabanov
43-46
The information on tropospheric layers with supercritical vertical gradients of refraction coefficient above the Black Sea has been given. This data has been obtained thanks to atmosphere sounding from an aircraft or helicopter by means of refractometer at an altitude ranging from 2 to 1500 meters.
COMPARISON OF OBSERVED AND MODEL WAVEFORMS OF Q-BURSTS
A. P. Nickolaenko, M. Hayakawa, M. Komatsu, T. Ogawa
47-56
Experimental waveforms of natural ELF transient signals (Q-bursts) are compared with model computations. Vertical electric field component of Q-bursts was recorded at Kochi (33.3° N and 33.4° E) in 2003–2005. Separate pulses were chosen recoded in fair weather conditions in a wide frequency band with the help of a “ball” antenna. The computations were performed for the uniform isotropic spherical Earth – ionosphere cavity model with the linear frequency dependence of the wave propagation constant. Pulses arriving from different distances were compared, and each pair showed a high reciprocity of waveforms. Coincidence indicates that the model applied is correct, it simultaneously shows that distances are accurate found from the time delay between the first pulse and the antipodal and round-the-world wave.
INSTRUMENTAL-PROGRAM SYSTEM FOR STUDY OF METEOROLOGICAL RADAR ECHO
Е. N. Belov, О. А. Vojtovich, Т. А. Makulina, G. А. Rudnev, G. I. Khlopov, S. I. Khomenko
57-63
The description of instrumental-program system for study of clouds and precipitation is described. The system includes double-frequency radar, optical-television device for visual observation of the objects under inspection, calibration device to provide absolute measurements of radar reflectivity in the dynamic range up to 40 dB, control unit for the antenna orientation and interface unit for coupling radar to a personal computer. The software developed permits to control the radar and provide measurements of altitude profile of spectral-correlation parameters for study of turbulence characteristics of meteorological objects.
Study of microwave superconducting transmission line in the strong electromagnetic fields
A. A. Lavrinovich, E. V. Khramota, N. T. Cherpak
64-68
This paper presents the analysis of microwave superconducting transmissions lines on the basis of telegraph equations in the case when a superconductor is characterized by nonlinear linear resistance and inductance, depending on the level of input signal. Dependences of the output power and phase coefficient of propagation constant on the input power are obtained for a section of nonlinear transmission line. Comparison of results of theoretical analysis and experimental study of X-band high-temperature superconductors (HTS) of coplanar line allowed determining characteristic input power, which is introduced as phenomenological one at theoretical analysis.
Coupled disk dielectric resonators WITH whispering gallery MODES IN THE millimeter wave band
V. N. Derkach, R. V. Golovashchenko, O. V. Goroshko
69-73
The results of experimental study of spectral and field characteristics of single and coupled disk dielectric resonators (DDR) with whispering gallery modes (WGM) by means of the computerized measuring set are presented. The possibility of design of controlled EHF elements on the basis of coupled DDR for the probable application in terahertz and optical frequency ranges is shown by the example of five coupled resonators.
OPTIMIZATION OF OPERATION OF THE DIFFRACTION RADIATION OSCILLATOR ON HIGHER SPACE HARMONICS OF PERIODIC STRUCTURE
V. S. Miroshnichenko, V. K. Korneenkov, Ye. B. Senkevich, D. V. Yudintsev
74-80
The outcomes of experimental examinations of the diffraction radiation oscillator (DRO), working on higher space harmonics of diffraction grating are presented. It is shown, that due to a choice of an open resonant system of the DRO it is possible to lower influence of ohmic losses growth in a diffraction grating on output performances of the DRO at a raise of the number of a space harmonic. The comparison of starting current and output power of DRO, working on 1-st, 2-nd and 3-rd space harmonics of a diffraction grating is submitted.
MULTIFREQUENCY SELF-OSCILLATIONS IN SEMICONDUCTORS STRUCTURES WHITH TWO LINKED AVALANCHE P–N-JUNCTIONS
K. A. Lukin, P. P. Maksymov
81-87
The results of the numeral solution to the equations of diffusive-drifting model of pn–i–pn-structures with abrupt avalanche p-n-junctions are presented. The regime of multifrequency self-oscillations in Ge, Si and GaAs pn–i–pn-structures with the constant reversed bias is discovered. The mechanism of their excitation is explored and the spectral analysis is executed. It is shown that the semiconductor structure with abrupt p-n-junctions is the self-oscillations system. On the basis of the back displaced Ge, Si and GaAs pn–i–pn-structures with optimum parameters multifrequency generators of SHF-range can be created.
EXPANDING OPPORTUNITIES FOR CONTINUOUS BAND OF ELECTRICAL FREQUENCY CHANGE IN CLINOTRON: EXPERIMENTAL INVESTIGATION
V. G. Chumak, S. V. Pankov
88-92
In this paper possibilities of the extension of the continuous frequency tuning bandwidth in the clinotron operating frequency range are studied. The most attractive approach is optimization of the geometry of the slow-wave oscillatory system of the tube. It is shown that by means of the distance variation between the slow-wave structure and the opposite cavity wall it is possible to provide the continuous frequency tuning bandwidth up to 20–25 %.
INFLUENCE OF SYNTHESIS TIME OF THE ACTIVE MATERIAL AND INTENSITY OF PUMPING ON TERAHERTZ GAS-DISCHARGE HCN-LASER PARAMETERS
V. K. Kiseliov, V. P. Radionov, N. F. Dakhov
93-96
The indirect measurement of time of synthesis of an active material of the HCN-laser is executed. The reasons of its influence on the laser parameters are analysed. The method of magnification of power and efficiency of the laser is offered and tested.
SIGNAL DETECTION IN GAUSSIAN NOISE BY USING THIRD-ORDER TEST STATISTICS
А. V. Тоtsky
97-102
The detection problem is considered for deterministic signal observed in additive mixture with Gaussian noise by using test third-order statistic on the basis of Neyman-Pearson criterion and theory of statistical decisions. The forming of detection statistic in the form of peak estimate of third-order moment function at the matched filter output has been suggested. Results of computer simulation demonstrating the benefits of third-order statistics comparing with conventional second-order statistics are represented.
INTERACTION OF ARTIFICIAL DNA-LIKE STRUCTURES IN MICROWAVE BAND: THE POLARIZATION SELECTIVITY OF WAVE RADIATION
I. V. Semchenko, S. A. Khakhomov, A. P. Balmakov
103-108
Research on polarization properties of DNA is chosen
by us as the one of paramount importance due to the asymmetry of the DNA form.
The preliminary theoretical calculation has shown that the DNA form is optimum
for formation of a circular electromagnetic wave under the resonance condition
(
~10 nm).
This conclusion has been proved for the metal DNA-like helices in a microwave
range in accordance with the principle of scaling. In the given work it is
experimentally confirmed the presence of the effect of polarization selectivity
when microwave waves have double reflection from DNA-like helical elements
depending on their sign (the right and left helices). It is shown that the
circular polarization of waves plays an important role at interaction of
microwave waves reflected from the artificial DNA-like structures. Probably,
the identical effect takes place in some processes that involve DNA in
biological organisms cells, but in far ultraviolet radiation that is close to
the X-ray range.