Contents
Section 1. Topics on computer simulation in electrodynamics
Application of Luneburg lens for measuring reflectivity on bistatic facility
R.V. Gilmutdinov, N.L. Menshikh, S.A. Fedorov
Abstract
In this paper modernization of a bistatic facility by improving a gigahertz-range frequencies feed through the use of a Luneburg lens is described. The proposed modification enables the formation of electromagnetic field over a wide frequency band with the required amplitude distribution in the area where the flat material sample is placed, thereby increasing the accuracy of determining bistatic scattering characteristics. In problems of determining the reflection coefficient magnitude of materials in free space, a significant source of measurement error is the diffraction effects associated with the shape and size of the sample. Reducing their influence is achieved by optimizing the structure of the incident electromagnetic field in the area where the sample under study is located. Within this work, numerical modeling was performed using the method of moments of field formation by an irradiator with a lens and the process of measuring the reflection coefficient of electromagnetic wave from a material sample using a modernized irradiator. The simulation results show that employing an illuminator with a hyperbolic lens reduces the amplitude of the incident electromagnetic wave at the edges of the sample. The radiation pattern of the modernized system features a lower level of sidelobes, which decreases the influence of direct transmission between antennas in the bistatic scheme on the accuracy of reflection coefficient measurements. Numerical modeling of the reflection coefficient measurement experiment and comparison with analytical calculations demonstrated that the use of the Luneburg lens feed reduces the error in measuring the reflection coefficient magnitude across a wide frequency range and angular sector.
Keywords: Luneburg lens, FEKO, reflection coefficient, edge diffraction
Section 2. Topics on experimental electrodynamics
Formation of near-surface radiation maxima by eigenwaves of thin metal rods
A.M. Lebedev, T.A. Furmanova, V.N. Semenenko, A.D. Semizbaev
Abstract
Near-surface intensity maxima of radiation from thin cylindrical conductors, which represent round metal rods with radius much smaller than the wavelength, are formed by eigenwaves running along the rods. Intensity maxima are achieved on diffraction cones around the rods' orientation directions. The near-surface mainlobe and its closest sidelobes have the same shape both in directional diagram of the dipole antenna and in two-position scattering diagram of the metal rod provided the lengths of the dipole arm and the rod are equal. Directional diagram of the current, which runs along the same length thin rod with phase velocity equal to the speed of light, also has very similar dependence of radiation intensity in the angular interval where the near-surface maxima exist. Formation of the near-surface maxima around thin cylindrical elements of metal structures worsens directivity and jam resistance of antennas, results in additional directions of increased scattering from illuminated objects. Eigenwave of the metal rod exists in the region bounded by radial coordinate, and the wave's amplitude decreases to zero with expansion of the boundaries of the region, where it is formed, to infinity. Best results in the near-surface radiation maxima suppression can be obtained by absorbing eigenwave of the cylindrical conductor immediately near the location of the eigenwave's generation.
Keywords: near-surface maximum, two-position scattering diagram of metal rod, directional diagram of dipole antenna, eigenwave of the metal rod
Synthesis and study of a thin-film non-evaporable getter Ti-Zr-V coating with low activation temperature for microelectronic devices
А.С. Набоко, В.И. Полозов, А.П. Шматков, А.В. Дорофеенко, А.М. Мерзликин, И.А. Рыжиков
Abstract
We report a development and experimental study of a thin-film non-evaporable getter (NEG) based on the three-component Ti-Zr-V system. A coating with a stoichiometry close to the target Ti31Zr18V51 composition was obtained using magnetron sputtering with three independent sources. A specially designed vacuum test bench con rmed the possibility of activating the coating at a temperature of 200°C for 24 hours. Dynamic residual pressure curves demonstrated the e ectiveness of the activated getter in maintaining vacuum in an isolated chamber for several hours, unlike the non-activated or saturated state. The obtained results con rm the promise of applying the synthesized coating in devices containing microelectronic components sensitive to overheating and align with current trends in lowering the activation temperature of NEG materials. For a complete characterization of the coating’s sorption properties regarding key gases (CO, H2), further development of a specialized experimental setup is required.
Keywords: optical antenna, integrated optics, silicon nitride, optical phased array, spatial scanning, LIDAR
Editorial address: 13 b. 6, Izhorskaya st.,
This site respects your rights and maintains confidentiality when filling out, transmitting and storing your confidential information.
Placing an application on this site means your consent to the processing of data and the further transfer of your contact information to our company.
Personal data means information related to the subject of personal data, in particular the name, contact details (email address) and other data classified as personal data by Federal Law of July 27, 2006 No. 152-FZ “On Personal Data.”
The purpose of processing personal data is to inform about the services provided by our company.