Analysis of methods for measuring the dielectric properties of materials in the microwave range of wavelengths.

One of the modern trends in the development of communication systems, information and telecommunication systems, air traffic control systems, etc. is the transition and development of higher-frequency wavelength ranges. In this regard more and more stringent requirements (in terms of spectrum, out-of-band and spurious radio emission, and in the shape of the output signal) are imposed on radio engineering devices that transmit and receive microwave radio signals. As a result, the requirements for the design and functional features of microwave electronic devices are increasing. One of these requirements is to assess the degree of compliance with the required values of dielectric properties of materials used in the design of microwave electronic devices. This requirement is justified by the fact that the electrical parameters of such microwave devices as: strip filters, power dividers, printed antennas and others, directly depend on the dielectric properties of the materials used in their substrate designs. In this regard, three main methods have now emerged for assessing the dielectric properties of materials: the resonant method, the non-resonant method, and the free space method. Aim. The aim of this article is to carry out a comparative analysis of the known methods for measuring the dielectric properties of materials in the microwave range of wavelengths and devices for their implementation. Materials and methods. The authors of the article reviewed the scientific literature of domestic and foreign publications. Results. For each of the methods for measuring the dielectric properties of materials, their main idea, practical implementation, a mathematical model for processing experimental data and areas of application are given. The advantages and disadvantages for each of the methods for measuring the dielectric properties of materials are given too. Conclusion. The applicability of each of the considered methods depends on such factors as: the shape of the investigated dielectric material, its state of aggregation, the possibility of measuring amplitude or complex transmission and reflection coefficients, the presence of an anechoic chamber, etc.

Specific Features of Volume-modular Technology Application in the Design of Microwave Electronic Devices

State of problem. Today a significant part of passive microwave electronic devices is implemented in the form of single-layer structures. In some cases, such approach leads to an increase in the overall dimension’s characteristics of electronic equipment. Moreover, the application of single-layer microwave boards leads to the complexity of replacing individual functional units. Therefore, the replacement of the entire microwave board is required to improve any of its functional part. It is nonprofit economically and inefficient technologically. Significant progress in eliminating the above-mentioned disadvantages may be achieved by the application of volume-modular technology of design microwave electronic devices. Purpose. The purpose of the research is to present a brief overview of the features of the application of volume-modular technology in the design of microwave electronic devices of modern radio-electronic equipment. The volume-modular way of implementing microwave devices is described. It allows improving their weight and overall dimension characteristics and at the same time maintaining and increasing their functionality. The basic principles of design of volume modular microwave electronic devices are formulated. The results of numerical simulation of the electrodynamics characteristics of a strip-slot transition are presented. The method for quantitative assessment of the influence of volume-modular technology on the weight and dimensions characteristics of microwave electronic devices is considered. The main advantages and disadvantages of volume-modular technology are listed. Results. We demonstrate a possibility of reducing the overall dimensions characteristics of passive microwave electronic devices by more than 10 times while maintaining their electrical parameters. Each component is presented in the form of a structurally separate and complete board with unified overall and connecting dimensions. The standard electromagnetic coupling between functional parts makes it possible to assemble microwave electronic devices with specified electrodynamics characteristics from the base elements.

Shielding Device for Microwave Electronic Components of a Multilayer Board for the AFAR Transceiver Module for Space Purposes

A method of shielding the elements of a microwave module based on the principles of forming a Faraday cage, with different power and different frequency paths of the AFAR receiving-transmitting module, excluding their mutual electromagnetic influence, is presented. A description of the structure of a multilayer board and various structural elements is given, allowing to limit (screen) the signal in a small volume, commensurate with the size of a monolithic integrated circuit or a set of monolithic integrated circuits, isolating parasitic electromagnetic interference. Polyimide is considered as a dielectric material of a multilayer microwave board for use in space technology devices, as well as promising design solutions for reducing the mass and dimensions of the module.

Low-Cost Additive Manufacturing Techniques Applied to the Design of Planar Microwave Circuits by Fused Deposition Modeling

This work presents a study on the implementation and manufacturing of low-cost microwave electronic circuits, made with additive manufacturing techniques using fused deposition modeling (FDM) technology. First, the manufacturing process of substrates with different filaments, using various options offered by additive techniques in the manufacture of 3D printing parts, is described. The implemented substrates are structurally analyzed by ultrasound techniques to verify the correct metallization and fabrication of the substrate, and the characterization of the electrical properties in the microwave frequency range of each filament is performed. Finally, standard and novel microwave filters in microstrip and stripline technology are implemented, making use of the possibilities offered by additive techniques in the manufacturing process. The designed devices were manufactured and measured with good results, which demonstrates the possibility of using low-cost 3D printers in the design process of planar microwave circuits.

Research of computational error behavior at the numerical simulation of curved electrodynamic systems

The paper presents an analysis of the approach to the numerical study of vacuum microwave electronic systems by finite-difference time-domain (FDTD) method. The results on approximating the boundary between two materials are presented. The influence of changes in the geometric shape of the resonator on the frequency obtained in the numerical experiment is analyzed. The sensitivity of the boundary approximation methods to small changes in geometric parameters is investigated.

Gyroton with the Corrugated Resonator

A new type of high-power electronic device—a gyroton with a corrugated resonator—is described and investigated. Spatial bunching of the electron beam does not occur in this device, however, highly efficient electron beam power conversion into the rotating electromagnetic field power is possible. The rectilinear electron beam deviates from the axis by the slow TM11 wave, then it gives up longitudinal energy to the same wave with more than 78% efficiency, and an output power up to 30 MW. The developed mathematical model of the interaction of the relativistic electron beam with an irregular circular waveguide and resonator fields presented in this article can be used to calculate and optimize the processes occurring in various microwave electronic devices, such as gyrotrons, gyrotons, TWT, Gyro-TWT, and BWT.