Influence of the cylindrical luneburg lens discretizayion on its antenna radiation properties

Исследуемая цилиндрическая линза Люнеберга представляет собой радиально неоднородную слоистую структуру. Исследуется влияние количества слоев дискретизации линзы на ее характеристики излучения. Рассмотрено четыре способа дискретизации линзы, для каждого из которых получены зависимости КНД от количества слоев, а также построены диаграммы направленности для варианта линзы из трех слоев и внешнего радиуса 3λ. Для расчета диаграмм направленности и КНД использовалась математическая модель, созданная на основе аппарата тензорных функций Грина стратифицированных сред в цилиндрической системе координат. Определен оптимальный способ выбора закона изменения толщины и диэлектрической проницаемости слоев.The cylindrical Luneburg lens under analysis has a radially unhomogeneous layered structure. The influence of the number of layers on lens antenna radiation properties is investigated. Four ways lenses discretization is considered. For each way antenna directivity is analyzed. Radiation patterns of three-layer Luneburg lens and 3-wavelength outer radius are shown. To calculate radiation patterns and antenna directivity a model based on Green’s functions of cylindrical layered structure was used. The optimal method of cylindrical Luneburg lens layer’s permittivity and thickness choice is suggested.Исследование выполнено за счет гранта Российского научного фонда (проект №14-19-01396)

Radiation Patterns of Patch Antennas on Coated Conducting Cylinders

The development of the Internet of Things and communication systems of the fifth generation leads to the need to place many antenna elements in a limited volume. Therefore, wearable electronics antennas are often located directly on the device body. Such surfaces can often be thought of as a conducting cylinder covered with a dielectric material. The task of analysing the radiation patterns of antennas located on such surfaces becomes urgent. This paper shows a method for analysing antenna directivity diagrams using the Green's functions method of cylindrical layered media. This method allows to obtain in an analytical form the expressions for the analysis of such structures, which makes it possible to reduce the cost of computer time in modelling. The presented results show what kind of distortions are introduced into the radiation pattern of antennas located on a cylinder compared to an antenna located on a flat surface. © 2021 Institute of Physics Publishing. All rights reserved.The research was executed by the Grant of the Ministry of science and higher education of the Russian Federation (Project N 0836–2020–0020)

Влияние радиуса идеально проводящего цилиндра на диаграмму направленности расположенной на нем патч-антенны

In this paper, we consider the change in the directional pattern of a microstrip patch antenna located on a perfectly conducting plane and a cylinder covered with a dielectric layer. The mathematical apparatus of the Green’s tensor functions for flat and cylindrical layered metaldielectric structures is used to calculate field characteristics. The obtained results are of special interest in the design of conformal single radiators and antenna arrays located on curved surfaces that can be approximated by a cylinder, for example, the fuselage of small-sized aircraft or supports for the installation of antenna systems. It is demonstrated that the curvature of the base surface for a single element has little effect on the radiation pattern within the width of the main lobe; nevertheless, the increase in the radius of the used cylinder influences the level of the back lobe significantly. Chechetkin V. A., Shabunin S. N., Korotkov A. N. Influence of the radius of a perfectly conducting cylinder on the radiation pattern of a patch antenna. Ural Radio Engineering Journal. 2022;6(1):54–66. (In Russ.) DOI: 10.15826/urej.2022.6.1.002. В работе рассматривается влияние кривизны проводящей поверхности со слоем диэлектрика, на которой расположена микрополосковая патч-антенна, на ее диаграмму направленности. Для расчета полевых характеристик используется математический аппарат тензорных функций Грина для плоских и цилиндрических слоистых металло-диэлектрических структур. Полученные результаты представляют интерес при проектировании конформных одиночных излучателей и антенных решеток, расположенных на криволинейных поверхностях, которые возможно аппроксимировать цилиндром, например фюзеляж малогабаритных летательных аппаратов или опоры для установки антенных систем. Показано, что кривизна поверхности основания для одиночного элемента слабо влияет на диаграмму направленности в пределах ширины главного лепестка, тем не менее увеличение радиуса используемого цилиндра значительно влияет на уровень заднего лепестка. Чечеткин В. А., Шабунин С. Н., Коротков А. Н. Влияние радиуса идеально проводящего цилиндра на диаграмму направленности расположенной на нем патч-антенны. Ural Radio Engineering Journal. 2022;6(1):54–66. DOI: 10.15826/urej.2022.6.1.002.

How the green's functions may be used for correcting measurements of transmission through flat homogeneous and sandwich-type dielectric sheets

The Green's functions of layered structures are used for analysis of measurement errors of transmitting losses through solid and sandwich-type dielectric structure. Influence of the spherical waves excited by radiators in the near zone is under investigation. As the simplest antenna, the Huygens element was used for calculations. The model of equivalent electric circuits was used for layered structure modelling. The transmitting losses of electromagnetic waves versus frequency for different dielectric sheets are shown. Influence of the distance between antennas on the transmitting losses measurements is analyzed. It is proposed to use the suggested method to analyze the accuracy of the transmission coefficients measurements if the horn antennas are used. © 2020 American Institute of Physics Inc.. All rights reserved.This work was supported by the Grant of the Ministry of Science and Higher Education of the Russian Federation (project no 8.2538.2017/4.6)

Investigation of spherical and cylindrical Luneburg lens antennas by Green's function method

Luneburg lens antenna radiation fields are calculated with Green's functions of spherical and cylindrical layered structures. Electric field components for Luneburg lenses excited by a linear and circular polarized antenna are analyzed. Co-polarized and cross-polarized field radiation patterns are shown. Reflection from the lens, losses in the lens material, spillover and polarization loss are taken into account for antenna gain calculation. The proposed method significantly reduces computing time for multilayered lens in comparison with the most commonly used in antenna design. © 2015 Radio Society (Mauritius)

Current trends for improving the design of membrane devices for photoautotrophic biosynthesis is light dependent microorganisms

Modern trends in improving the design of membrane devices for photoautotrophic biosynthesis dependent lighting microorganisms aimed at a significant increase in the productivity of valuable products from biomass of microalgae and obtaining on the basis of their individual useful substances (drugs) used in various industries and medicine. In film devices effectively the processes of heat - and mass-exchange with the gas comes into contact with the culture fluid flowing as a film on a transparent film-forming surface is STI in its light intensity and autotrophic biosynthesis occurs only in the presence of a mixture of air with carbon dioxide. Thus, completely eliminated the accumulation of metabolic products due to their continuous removal from film culture liquid with the process gas, which is not typical for devices of other types. Small size membrane bioreactors may increase the degree of saturation of the liquid carbon dioxide with the possibility of changing the concentration of gas in the culture fluid and to ensure the cultivation of microorganisms with a specified biomass yield. At present up to date-developed a significant number of ways to ensure contact of the gas with the liquid (bubbling, gas-lift, mechanical stirring, jet, membrane, etc.) on the basis of which an industrial bioreactor, with various "stress" effect. It is believed that for the cultivation of the most optimal are bioreactors with mechanical stirring of the liquid, which allow the greatest productivity of biomass. However, the applied model of a mechanical mixing device to create a work whose cavity of the bioreactor chaotic, disorganized mixing, which contributes to the emergence, insufficient for the sustenance of the cell cultures and microorganisms. Analysis of the interactions of the gas with the liquid film devices showed the need to create a new generation of bioreactor with intensive mass transfer without the possibility of limiting the productivity of biotechnological systems. The work shows a consistent change in structural elements of membrane bioreactors to increase the efficiency of their operation

Компактная периодическая микрополосковая антенна вытекающей волны с периодически установленными короткозамыкателями и способностью сканировать в прямом и обратном направлениях

Поступила: 24.01.2022. Принята в печать: 15.03.2022.Received: 24.01.2022. Accepted: 15.03.2022.Compact size, elliptical polarization, a low-sidelobe-level microstrip leakywave antenna with short pins on one side of the sheet is described in the paper. The suggested antenna consists of 7 sheets that are periodically put on the antenna structure, with one of the edges of the sheet being incorporated with short-circuit pins. The proposed antenna has effective decrease in antenna size good scan capability, and reduction in sidelobe level In comparison with another types of antennas. A set of simple and effective equations is used to determine the operating range of the antenna. As elucidated by simulation results, the scanning process is carried out from 11° to –15°, at the rate of 26% as the frequency changes from 22.8 GHz to 27.8 GHz.В статье описана компактная микрополосковая антенна вытекающей волны с излучающими элементами, имеющими с одной стороны короткозамыкатели, формирующая поле эллиптической поляризации с низким уровнем боковых лепестков. Предложенная антенна состоит из 7 прямоугольных печатных излучателей, последовательно возбуждаемых микрополосковой линией, каждый из которых замкнут с одной стороны проводящими штырями с экраном. По сравнению с другими антеннами, предложенная имеет меньшие размеры, хорошую способность частотного сканирования и уменьшенный уровень боковых лепестков. Для определения рабочего диапазона использованы достаточно простые выражения. Как показано в результате моделирования в среде Ansys HFSS, сканирование обеспечивается в диапазоне углов от 11 до –15 градусов при изменении частоты на 26 % от 22,8 до 27,8 ГГц.The research is executed by the grant of the Ministry of Science and Higher Education of the Russian Federation (Project No. 0836-2020-0020).Исследование выполнено в рамках гранта Министерства науки и высшего образования Российской Федерации (проект № 0836-2020-0020)

Radio Electronics Development Trends (Review of the International Conference)

Поступила: 18.07.2020. Принята в печать: 30.07.2020.Received: 18.07.2020. Accepted: 30.07.2020.Данная статья посвящена обзору тенденций развития радиоэлектроники, которые были обозначены в ходе проведения Международной конференции Ural Symposium on Biomedical Engineering, Radioelectronics and Information Technology в мае 2020 г. в Екатеринбурге. Проводится анализ тематик конференции в секции радиоэлектроники, связанных с перспективными телекоммуникационными технологиями, в том числе касающихся разработки антенно-фидерных устройств, измерения электрофизических параметров материалов и т.д.This article is devoted to the overview of the trends in the development of radio electronics, which were identified during the International conference Ural Symposium on Biomedical Engineering, Radioelectronics and Information Technology in May, 2020 in Yekaterinburg. We analyze the topics of the conference in the radio electronics section related to promising telecommunication technologies, including those related to the development of antennas, microwave devices, electrophysical parameters of materials, etc

Giant bleeding post-traumatic thoracic sarcoma management: A case report

The heterogeneity of thoracic wall tumors often represents challenging clinical entities for surgeons due to diagnostic and treatment complexities. The primary tumors, metastases, or direct invasion from intrathoracic structures comprise almost half of all cases on average that are proved to be malignant. Surgery treatment usually leaves large chest defects that require further extensive reconstruction and multimodal management including radiotherapy and chemotherapy. We report a rare case of a giant (30 cm) post-traumatic bleeding thoracic sarcoma treatment in a 70-year-old female. The use of our modified Verneuil technique to close the extensive postoperative skin defect optimized surgical wound management and provided good functional and aesthetic results. Four-year follow-up outcomes after surgical and adjuvant radiation therapy reported a high level of tumor control and showed no evidence of postoperative disease recurrence