A.A. Bulgakova, N.N. Gorobets, V.A. Katrich, and V.A, Lyaschenko
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkiv, 61077, Ukraine
Formation of Directional Patterns of Planar Antenna Arrays
Results of computer simulation are presented, concerning the effect of aperture geometry in a planar antenna array upon the antenna pattern. It has been shown that the level of interference peaks, as well as of the near and far side lobes of the antenna pattern within one of the observation planes depends on the number and mutual position of radiators within the other orthogonal plane.

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L.Ye. Kopilovich A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Regular Methods for Constructing the Aperture Synthesis Systems on Hexagonal Arrays
A method for constructing nonreduntant configurations of elements on hexagonal arrays is presented. It is based upon difference sets. The application of these particular constructions to the systems of radioastronomical and optical aperture synthesis is described. In addition, the procedures for setting the configurations that provide for complete uniform coverage of given hexagonal domains in the spatial-frequency plane are outlined.

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N.N. Gorobets, A.N. Dumin, and O.A. Dumina
V. Karazin National University of Kharkiv,
4, Svoboda Sq., Kharkiv, 61077, Ukraine
Transient Fields Radiated from the Open End of a Coaxial Waveguide with an Offset Internal Conductor
The problem of radiation from the open end of a coaxial waveguide with an offset internal conductor which is excited by a time-dependent wave field is solved in the time domain. A TEM-mode with a Gaussian pulse waveform incident upon the open end of a coaxial waveguide is considered as the source. The influence of the flange upon the radiated field parameters is investigated. The possibility of using dielectric insertions in the aperture to increase the emission along the normal to the aperture is analyzed.

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A.O. Perov, V.I. Tkachenko, and A.A. Kirilenko
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Comparative Analysis of Open-Ended Waveguide Characteristics, Obtained by Exact and Aperture Models
The problems of characteristics calculation for antenna with circular aperture of radiation are considered. The exact model based on the Wiener-Hopf method is realized and is used for verification of the Kirhhoff approximation for horn and waveguide radiators.

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O.I. Belous, A.I. Fisun, V.K. Êîrneyenkov, and O.N. Sukhoruchko
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Å-Polarized Modes of the Ìulti-Mirror Millimeter-Wave Band Open Resonator
Multimirror open resonator with echelette mirror is described. The spectrum and field topology of E-polarized modes is investigated in 8 mm wave range. The application of this resonator as oscillation system of electron vacuum devices is offered.

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I.Ya. Brovenko, I.V. Ivanchenko, N.O. Popenko, and R.E. Chernobrovkin
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Probe Design for Near-Field Measurements in the Millimeter Wave Band

On the basis of numerical simulations and experimental investigations the new probe design for measurements of amplitude and phase near field distributions in millimeter wave band has been developed. This probe is the rectangular waveguide, particularly filled with a dielectric. The probe’s capability is illustrated by the model experiment with the artificial dielectric.

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E.M. Ganapolskii
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Hyperrsonic Delay Lines of Microwave Signals

Hypersonic delay lines (HDLs) of microwave signals were suggested for the first time in IRE of Ukrainian NAS in 1961. Physical foundations for the HDL analysis and new line of science and engineering have been provided for development of the memory devices dedicated to the signal processing of microwave radiolocation. The overview of main results of the works carried out in IRE NASU is given in this paper. The principles have been considered, on which the transformation of electromagnetic waves into hypersonic ones is based. The method of hypersonic excitation by a surface slowed electromagnetic wave and the point transformation method with using piezoelectric ZnO films have been described. The main mechanisms of hypersonic absorption in crystalline acoustic guides at room and cryogenic temperatures have been considered. Effect of the longitudinal conversed hypersonic scattering in dielectric crystals at low temperatures is represented. This effect was discovered and studied in IRE NASU. The designs of broadband HDLs with uncooled acoustic lines and HDLs with effect of the conversed hypersonic scattering, have been described.

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D.V. Pavlenko and E.D. Prokhorov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkiv, 61077, Ukraine
Width of Current-Voltage Characteristics of InxGA1-xN Gunn Diodes

The impact ionization in GaN, InN an their compounds is studied. The width of voltage-current characteristics (CVC) and voltages enough to develop the impact ionization in Gunn diodes made from GaN, InN and their compounds are defined.

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