The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The article briefly reports the basic concepts and principles related to transmissions lines, modeling of linear networks, defining S parameters, and some elements relevant to microwave metrology and the design of network. The advantages and use of the scattering matrix and scattering parameters are discussed. Examples of the microwave networks provide a whole picture of the problem. Scattering matrix...
The results of numerical investigations of electrodynamic characteristics of multibeam triple-gap resonator are presented. The possibility of achieving the multiplicity equal to two ratios of frequencies the fourth higher mode to the frequency of the main mode is shown. This setting will provide a quasi sawtooth law of variation of the RF voltage on the resonator gaps. When tuning the frequency of...
The results of the research management capabilities of dispersion characteristics folded-waveguide with drift tubes according to functionality of system of designed TWT millimeter wavelength range. The proposed modifications of the folded-waveguide with an offset of waveguide side walls relative to coupling slots provide an effective dispersion management in the operating frequency range. Constructive...
The results of numerical investigations of electrodynamic characteristics of multibeam triple-gap resonator with two spaced beams of millimeter wavelength range are presented. The possibility of achieving the multiplicity equal to three ratios of frequencies the two higher modes to the frequency of the main mode is shown. Setting the frequency of the investigation modes was made by changing the parameters...
In this paper we propose an approach for the study and forecasting of the UAV fuselage stability at impact lightning. Example of forecasting the electromagnetic stability and thermal stability of the compartment UAV fuselage which made of composite material is discussed. The analysis of the study results shows the need to use technical measures to improve the stability of the UAVs fuselage at impact...
Nowadays such super-high frequency devices as a microstrip branch-line coupler are widely used in present day's radio technical systems. This article contains an analysis of how thickness of the compact two-branch-line coupler's thin elements affects its characteristics. A constructions miniaturization procedure involves replacement of a microstrip transmission line section by a lowpass filter, which...
Dual band compact 90-deg waveguide polarizer for satellite communication applications is presented. The polarizer is based on double ridge sections in square waveguide. A proposed compact and easy for fabrication design provides very high performances within two standard frequency bands. CAD-oriented full wave technique for analysis of polarizers is based on Galerkin method, mode matching technique...
The authors presented a technique of calculating the strength of the electric component of an electromagnetic field for solving problems of electromagnetic microwaves propagation in radio electronic devices for different purposes. The technique is based on representing the surface reflection of electromagnetic waves in the form of a set of elementary emitters, for example, of Hertz elementary electric...
A wide band compact 20 dB directional coupler has been designed, fabricated and tested for high power operation within frequency band 4–12 GHz. In order to obtain broad band frequency response a three-section asymmetric coupled strip-line directional coupler has been chosen. Since the phase shift between the even and odd modes appears by their propagation through the strip-line discontinuities, a...
The paper covers the ways of improving the efficiency of a tube Class E power amplifiers (PA) used in the output stage of high-power radio transmitters. Shifting PA in class E mode enabled to achieve anode efficiency of 88…93%. At the same time it led to a result that control and screen grid dissipated power in tetrode became one of the main factors hindering further improvement of PA characteristics...
Use of field emission cathodes with high density of electronic current is capable to improve characteristics of electrovacuum devices and to give additional acceleration in development of vacuum microelectronics. For obtaining high density of current it is necessary to increase efficiency and concentration of emission centers. Improvement of field emission of characteristics at production on the flat...
The current status of the various theoretical approaches to the description of turbulence in the electron flow and electronic devices of ultrahigh frequencies (UHF) is shown. A three types of turbulence in nonlaminar electron flow were considered. The first type of turbulence is caused by the intersection of the electron trajectories (eg, due to thermal velocities) and it is common to all the electron...
This report tells about researching of parametric generation in crossed fields. The main attention was preformed to interaction space formed by two coaxial cylinders with an axial magnetic field is a possible parametric generation of electromagnetic oscillations in the absence of the constant anode potential due to inhomogeneous magnetic induction components. Equations of motion were solved numerically...
The results of the calculation of the distribution of the magnetic field in the magnetic periodic focusing system with different screen configurations are presented. The calculations of the electron beam trajectories in the gun for different values of the field at the cathode are showed. The values of the magnetic field at the cathode depending on the ratio of the diameter of the screen to the outer...
This report summarizes the results obtained in the papers relating to the generation of high frequency signal in crossed electric and magnetic fields. We consider the radial resonator system, with two coaxial cylinders and inhomogeneous magnetic induction, and determine electron trajectories in crossed fields. Trajectories were determined in case of ac magnetic and electric fields with other frequency...
This paper presents research results of electron gun characteristics with one and seven field-emission cells each of them contained autoemitter made of carbon glass in the form of needle with the high aspect ratio geometry and pulling grid separated from the cathode by the vacuum gap. In the pulse mode with the potential difference between the cathode and pulling grid 2813 V from the single tip with...
The propagation of current and velocity sinusoidal modulation in plane diode using 2D numerical model is studied. The linear regions are obtained when the first harmonics of current and velocity between cathode and anode are increasing proportionally with increasing of harmonic in start points. For two cases of modulation in start points — modulation of current and modulation of velocity — numerical...
This report presents the results of calculation of electron-optical system consisting of a sheet CNT field emission cathode with a microgrid spaced from the surface of the emitter at 100 microns. On the basis of experimental data, it has been designed electron-optical system with a sheet CNT cathode with linear convergence of 6,25, and with the beam current density of 4,46 A/cm2. The thickness of...
The method and code of electron gun calculation in time domain are presented. The Poisson equation in 2D axial region is solved by integral equation method. For modeling in time domain algorithm «step by step» is used. Three meshes — one spherical and two rectangular — are used for potential calculation and equation of motion solving. The consistent scheme of distribution between mesh points of particle...
Possible ways for designing super-high power pulsed klystrons at significantly decreased operating voltages have been considered. They include the following: — the development of principles for designing klystrons with magnetron gun with anode modulation, positioning several such klystrons in a single solenoid with homogeneous magnetic field and summation of their output powers. — the development...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.