Films of cobalt oxide and nickel oxide on monocrystalline silicon substrates were obtained by electrochemical deposition from aqueous electrolyte solutions. Their structure and composition were studied by Raman microscopy and scanning electron microscopy. The results of the study by Raman spectroscopy showed that the obtained films are polycrystalline structures of cobalt (II, III) oxide and nickel (II) oxide, the crystalline perfection of which increases with an increase in the electrolyte temperature. It was found by scanning electron microscopy that nickel oxide films have a smoother surface, while cobalt oxide has a more developed structure consisting of lamellar crystals. The specific electrochemical capacity of cobalt oxide and nickel oxide films obtained under optimal conditions, measured by voltammetry, was 14.67 and 1634.08 F/g, respectively. The high specific electrochemical capacity of a nickel oxide film can be used to create efficient electrochemical devices and energy storage devices.

Effect of rapid thermal annealing temperature on the electrophysical properties of the ohmic contact of Ti/Al/Ni metallization with layer thicknesses of 20/120/40 nm to the GaN/AlGaN heterostructure with a two-dimensional electron gas on a sapphire substrate has been discovered by transmission line measurement and secondary ion mass spectroscopy methods. Rapid thermal annealing of the samples was carried out in a nitrogen atmosphere at the temperature ranging from 850 to 900 °C for 60 s. It has been discovered that a high-resistance heterostructure layer with a thickness of about 25 nm is located on the initial samples between metallization and the two-dimensional electron gas, which prevents the formation of ohmic contact. After rapid thermal annealing at the temperature of less than 862,5 °C, the metallization components interact with each other and with the heterostructure, which leads to the decrease in the thickness of the high-resistance heterostructure layer to 15–20 nm and to the nonlinearity of the I – V characteristic. At rapid thermal annealing temperatures in the range from 862,5 to 875 °C, the thickness of the high-resistance heterostructure layer decreases to several nanometers due to the interaction of Ti/Al/Ni metallization components with the heterostructure, which promotes the tunneling effect of charge carriers and formation of a high-quality ohmic contact with a resistivity of about 1⸱10^–4 Ohm∙cm² . With an increase of the rapid thermal annealing temperature over 875 °C, the interaction of the metallization and heterostructure components occurs throughout the entire depth, the two-dimensional electron gas degrades, and the I – V characteristic of the contact becomes nonlinear. The results obtained can be used in the technology for creating GaN-based products with a two-dimensional electron gas.

A double gate JFETs are often used in analog integrated circuits to provide an extremely low input current and capacitance when the top gate is controlled. Circuit synthesis and modeling of analog IC with such a field-effect transistor are possible only if there are models that adequately describe the features of its operation, namely, changing of the current-voltage characteristics by the top gate controlling when a constant reverse voltage is applied to the bottom gate. The article considers the modernization of the well-known electrical model of the double gate field-effect transistor for the LTSpice software, which includes taking into account the influence of the top gate voltage by connecting two series-connected functional voltage sources to the top gate, one of which ensures the coincidence of the measurement results and the simulation of the drain current at a low voltage between the top gate and the source, and the second – when the voltage between the top gate and the source is close to the cutoff voltage. A method for identifying the parameters of functional voltage sources is presented. The proposed model of a double gate field-effect transistor is advisable to use in the IC design of various analog devices, especially electrometric operational amplifiers and charge-sensitive amplifiers.

The problem of determining the number of objects in atomic force microscopy (AFM) images is considered. For the automatic (without operator participation) solution of this problem, segmentation is used, dividing images into areas containing objects of interest. Known segmentation algorithms based on the morphological watershed, defining the boundaries of areas by local minima of pixel brightness, having significant segmentation errors of AFM images and high computational complexity. Less computationally complex segmentation algorithms based on wave growth of regions require preliminary determination of the starting points of growth on AFM images under the control of an operator. Algorithms for growing regions without preliminary selection of the starting points of growth have the least computational complexity, but they segment the AFM image with a large error. To improve the accuracy of automatic determination of the number of objects in AFM images, a model and an algorithm for the wave growth of the regions of local maxima with their selection in decreasing order of values are proposed, which differ in the use of a brightness threshold varying from maximum to minimum to select growth pixels of regions or pixels attached to pixels of adjacent existing areas. The model provides parallel expansion of the boundaries of areas and automatic determination of the initial growth pixels during the segmentation process. The proposed model and algorithm make it possible to eliminate segmentation error characteristic of the marker watershed, growing areas and the Vincent – Sulli watershed, and thereby increase the accuracy of determining the number of objects in atomic force microscopy images.

The goal of the work is to find a solution, realization, and modelling of the algorithm for the compensation of a start random phase error of a quadrature signal, which began at the input of the receiver’s digital part. This algorithm also solves the problem of carrier frequency error offset. These errors have enough values for the lock-band of Costas PLL using minimum hardware resources. To complete this task, the realization and modelling algorithm problems of phase and frequency offset error corrections in Matlab Simulink IDE, arising from Costas PLL, were solved. This algorithm sets values errors for Costas PLL work stability. From the results of calculation and modelling obtained in the article, it follows that the developed model of the receiving path completely eliminates the probability of the error of a random initial phase and frequency offset in the receiver model of a QPSK signal, before the PLL loop is switched on, which significantly reduces the time of readiness for operation of this model.

With the increasing demand for quality of service (QoS) in today's multiservice networks, more and more attention is paid to the routing facilities. With the transition to new generation networks, the issues of improving routing algorithms and protocols seem to be especially relevant. The existing routing algorithms have been developed quite fully and, on the whole, function effectively if the optimization of the route selection is carried out according to one parameter. In the case of multi-criteria routing, specialists are faced with the problem of reducing many criteria to a single one by means of additive convolution. Less commonly, multiplicative convolution is used, since it is not always possible to apply multiplicative transformation to real physical processes. The problem of applying multiplicative convolution to various QoS requirements is to choose the weight coefficients for each of the parameters. In this paper, we analyze the choice of the optimal path for multicriteria routing, taking into account the weight coefficients and cost parameters on the basis of the above twolevel approach. The results of numerical modeling of the search for the optimal path for various values of weight coefficients and cost coefficients are presented. It is shown that when choosing a path for multi-criteria optimization, it is necessary to choose the coefficients of the additive convolution as the product of the weight coefficients and the cost coefficients directly. It has been found that the value of the probability of packet transmission affects to a greater extent the choice of the optimal path than the values of the coefficients for the parameters of delay, delay variation, and bandwidth.

Implementation of intensive development of technologies, systems, and services of mobile (cellular) communications (CC) of the fourth (4G) and fifth (5G), and by 2030 also the sixth (6G) generation, implying an increase by many orders of magnitude in the data transmission rates over radio channels of user interfaces, without adopting special measures and restrictions may be accompanied by a significant increase in the power of electromagnetic radiation of subscriber devices. This power, the upper limits of which are determined at the level of 23–26 dBm, that exceeds the safe levels for the population, determines the degree of acceptability of voluntary environmental risks from the penetration of 4G/5G/6G technologies and services into all spheres of human activity. The goal of the work is to assess the expected limitations on system characteristics of 4G/5G mobile communications when using population friendly electromagnetic radiation power levels of the user's radio equipment. As the analyzed characteristics of mobile communication systems, the maximum communication range, the maximum allowable data transmission rate and the allowable relative level of intranet interference are considered. A quantitative systemic analysis of these limitations, the results of which are presented in this work, makes it possible to substantiate the necessary system, technical and organizational solutions aimed at ensuring the necessary level of electromagnetic safety for consumers of 4G/5G/6G services in the context of the rapid development of these systems without compromising the efficiency of technologies of information services for modern society.

The purpose of this article is to present a method for improving the accuracy of calculating the height and response time of the missile initialization device at a given height, as well as a method for its structural implementation. The paper considers a time option for calculating the response height. I**-t is based on measuring the height of the projectile's flight at five points equidistant in time, from which the negative increment in heights is calculated, a formula that describes the vertical component of the projectile flight is drawn, the numerical calculation of which allows us to determine the projectile response time at a given height. As a structural diagram of the device, it is proposed to use a homodyne structure, the main advantages of which are easiness to implement, a small number of components and, as a consequence, small dimensions.

The article presents an improved technique for determining the required value of the image quality criterion for detection systems operating under distortion conditions. The calculated level of the quality indicator should be used to determine the fact of image distortion. On the basis of the proposed technique, a method of correlation detection in conditions of "smudge" and "defocusing" type distortions has been developed. The developed method of correlation detection is distinguished by the introduction of three stages: identification of distortions in the current image; formation of the convolution core based on the type and parameters of distortion; calculation of the number of iterations based on the required and current value of the image quality criterion. This made it possible to ensure the operation of the correlation detection method in conditions of distortion.

The purpose of this work is to develop a complex for research and measurement of parameters and characteristics of radio technical facilities (RTF). The complex is designed to generate ultra-wideband signals from 2 to 298 GHz in measuring systems that require the generation of complex radio signals: antenna measurements, research of radar characteristics and electrodynamic parameters of materials. The task is achieved by the fact that the quadrature signals of the results of the summation of the useful signal with noises that interfere with reflections and interference, are formed in the complex. Coherent signals are generated in analog form over four channels, and replaceable modules of the infrared frequency carrier and antennas form signals that are radiated into space. Replaceable blocks provide cascaded sequential mixing of the main signal with the local oscillator frequency. The selection of replaceable modules with a given local oscillator frequency makes it possible to provide signal radiation in the microwave and EHF frequency ranges.

Today’s practice of developing VHF radio systems paths widely uses MMIC as low-noise amplifiers. This approach is acceptable for radio systems operating in a relatively quiet electromagnetic environment. However, for systems operating in a complex interference environment of the VHF band, low-noise amplifiers with a lower gain and increased overload capacity are desirable. This requires maintaining a low noise figure and manufacturability of the device. Therefore, the solution to this problem requires the development of a low-noise amplifier of the VHF band with increased overload capacity, made on commercially available MMIC. This paper presents the results of a logical-heuristic synthesis of a VHF low-noise high-linear amplifier performed on an MMIC, utilising noiseless negative feedback technique. Analytical expressions are given for calculating the gain, the input gain compression point, input intercept points of the J-th order, and the noise figure of the structure. The analysis of the performance of the amplifier implemented on the MGA 62563 MMIC showed that, in comparison with other integrated solutions, increased overload capacity and structure linearity are provided. The high noise immunity and ease of manufacture of the device using commercially available components, make it a promising element in the design and modernization of VHF receiving and amplifying paths operating in a complex electromagnetic environment.

The purpose of the article is to substantiate the method and circuit design option for constructing an ultra-wideband radio receiver of the measuring system, mathematical modeling of the main parameters of the receiving path. It is shown the block diagram and general characteristics of the receiver. Including the dynamic range of received signals 111 dB, operating frequency range from 1 to 18 GHz. The article discusses the components of the receiver, such as: an automatic power control unit with a dynamic range of 50 dB and a tuning step of 1 dB, a preselector with six bandwidths 1–2,5; 2,5–4; 4–6; 6–11; 11–15; 15–18 GHz and a frequency conversion unit with three conversion steps. The structure is substantiated and the parameters of each of the blocks are given. A frequency conversion scheme with a final intermediate frequency of 0.75 GHz and a bandwidth of 500 MHz is considered in detail. Modeling of the noise figure, the distribution of the signal level along the receiver path from the input signal level and the results of modeling the output signal of the IF receiver.