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In this study, we propose a new design of a portable meter of reflection coefficients of radar absorbing coatings. An experimental comparison of the reflectivity meters of the new and traditional types is performed. The technical, operational, and cost advantages of a meter of a new type are shown. The efficiency of the meter calibration system was developed and proven, and the optimal geometric parameters of the antenna probe that ensures high-accuracy measurements of the reflection coefficient of radar absorbing coatings were determined.

A special system has been developed for measurement in free space of the following parameters of flat material samples: reflection and transmission coefficients, permittivity and permeability, angular dependence of the transmission coefficient, and temperature dependence of the reflection coefficient of rf absorbing coatings on metal substrates for normal incidence of electromagnetic waves at frequencies of 1–40 GHz. In order to increase the accuracy of the measurements various digital signal processing algorithms are proposed, including a way of suppressing the Gibbs phenomenon at the edges of the frequency band, as well as a method for correcting the results of S-parameter measurements during determinations of the permittivity and permeability of small samples.

The research results of the amplitude-phase field distribution in the near-field zone of the broadband lens horn antenna, which is used in the bench for measuring the electromagnetic properties of materials in free space, are presented. It is shown that the installation of a lens in the horn antenna leads to an increase in the uniformity of the amplitude-phase field distribution in the working area of the measurement bench, which increases the quality of complex permittivity and permeability measurements.

The results of the research and development of the unified radiotechnical characteristic of aircraft radomes are presented: an increase in the level of antenna side radiation, associated with the presence of a radome in front of the antenna. It is shown that for an objective assessment of the radio engineering quality of radomes the integral characteristic is best suited – the average increase in the level of antenna radiation power in the required sectors of viewing angles. It has been demonstrated that this characteristic weakly depends on the properties of the antenna with which the radome is estimated.

Specialized measurement bench is developed for measuring reflection and transmission coefficients of electromagnetic wave of material samples in free space, complex permittivity and permeability of sheet samples, angular dependences of transmissivity of materials and temperature dependences of reflectivity of metal backed radar absorbing materials at a normal incidence of electromagnetic wave in the frequency range from 1 to 40 GHz.

The complex electrical permittivity of industrially produced organic solvents of several classes with different abilities to form hydrogen bonds, such as ketones (acetone, 2-butanone), alcohols (ethyl alcohol, isopropyl alcohol), acetic esters (ethyl acetate, propyl acetate, butyl acetate), hydrocarbon solvents (toluene, ortho-xylene, heptane, solvent Nefras), chlorine-containing solvents (carbon tetrachloride, tetrachlorethylene), as well as a mixed solvent based on acetone, butyl acetate and ortho-xylene of brand R-5A, were studied. The frequency dependences of permittivity were measured by the coaxial probe method in a wide frequency range from 200 MHz to 20 GHz. It is shown that the chemical nature of solvents has a significant effect on their permittivity. It was found that solvents with weak hydrogen bonds (hydrocarbons and chlorine-containing solvents) have low values of the permittivity (not higher than 2.6) and negligible dielectric losses. Solvents with moderately strong bonds (acetic acid esters and ketones) have high values of permittivity with pronounced frequency dispersion, noticeable dielectric losses and Debye relaxation frequency above 20 GHz. Strong hydrogen bonded solvents (alcohols) are characterized by high values of the permittivity with significant frequency dispersion and Debye relaxation frequency below 1.5 GHz.

Vanadium dioxide (VO2) is a material with a metal-insulator phase transition. We report a way of application of VO2 thin films as functional elements of reconfigurable parallel plate waveguide array (PPWA). The PPWA presented here is designed to work in X, Ku and K bands. A transmission coefficient of the array with VO2 elements can be altered using temperature by more than 10 dB across the entire experimentally studied frequency range. We demonstrate a method of design and manufacturing of the PPWA. The PPWA may be used as a basic component in more advanced reconfigurable devices.

The purpose of this work is to report an accurate calculation technique of special compensation layer to minimize the boresight errors of the antenna radome system. The compensation layer with variable value of the layer thickness allows to substantially reduce boresight errors corresponding to radome in scanning directions. There was calculated and simulated a special compensation layer for the antenna radome of the aircraft where the high results of boresight errors reduction were reached.

This paper presents some numerical and experimental results in respect of reduction of the scattering properties of phased arrays outside their operating range using the band-stop frequency-selective structures (FSS). It reviews the phenomenon of incomplete non-suppression of separate Bragg lobes being caused by the formation of a Fabry-Perot cavity between the FSS and the conductive screen of the phased array. The reviewed approach has been applied to reduce the BSP of the L-band phased array on the basis of the Vivaldi radiator. The matching characteristics have been obtained (SWR < 2 with in-phase excitation and SWR < 3, when phased by beam at −45° direction) and the PA directionality. An integrated use of the band-stop FSS and absorbent material has allowed the amplitude of Bragg lobes to be reduced by 5–20 dB within the 8–18 GHz frequency band.

A model for calculating the field scattered by the antenna of an aircraft radar with consideration for the radome is described. Backscattering patterns of phased antenna arrays with and without a radome are presented. Substantial contribution of diffraction lobes into the radar visibility of the antenna is noted.