SWITCHING SCANNING ANTENNA SYSTEM BASED ON A FLAT LUNEBERG LENS WITH CONCENTRIC RINGS

Антенные системы с возможностью широкоугольного сканирования довольно часто используются в современных системах беспроводной связи и радиолокационных системах гражданского и военного назначения. Особое внимание привлекли Smart-антенны (антенны с коммутируемым лучом и адаптивные антенные системы), а также фазированные антенные решетки (ФАР). В работе рассмотрен вариант построения ФАР с коммутационным сканированием с диаграммообразующей схемой в виде плоской линзы Люнеберга, состоящей из системы концентрических диэлектрических колец, размещенных на подложке из материала Rogers 5880. Исследованы влияние кронштейна крепления для ФАР на диаграмму направленности, уровень излучения, снижение коэффициента направленного действия и уровня сектора сканирования в азимутальной плоскости. Максимальный диаметр ФАР 160 мм, полная высота такой антенны получилась 38 мм. Запитка осуществляется при помощи коаксиальных кабелей с волновым сопротивлением 50 Ом. Диаметр самой линзы Люнеберга был выбран 80 мм; полная высота линзы мм. Подложка имеет толщину мм, склеенная слоем клея толщиной 0.025 мм. Концентрические кольца на этой подложке имеют высоту 0.787 мм. Минимальная ширина концентрического кольца (внешнего) мм (при резке УФ лазером минимальная ширина перегородки между отверстиями равна 0.05 мм). Полосковые трансформаторы расположены на плате из материала Rogers 5880 и имеют толщину равную мм Scanning antennas with wide-angle scanning capabilities are widely used in the areas such as modern wireless communications and military and civilian radars. Among them, lens antennas with switched beams and phased array antennas (PHAR) attracted considerable attention. In this paper, we consider a variant of the construction of switching scanning PHAR with a diagram-forming scheme in the form of a flat Luneberg lens consisting of a system of concentric dielectric rings placed on a substrate made of Rogers 5880 material. We studied the effect of the PHAR mounting bracket on the presence of its influence on the radiation pattern, the radiation level, the decrease in the directional coefficient, and the level of the scanning sector in the azimuth plane. The maximum diameter of the PHAR is 160 mm, the full height of this antenna is 38 mm. The power supply is carried out using coaxial cables with a wave resistance of 50 Ohms. The diameter of the Luneberg lens itself was chosen 80 mm; the full height of the lens is H =0.939 mm. The substrate has a thickness of t =0.127 mm, glued with a layer of glue, 0.025 mm thick. The concentric rings on this substrate are 0.787 mm high. Minimum width of the concentric ring (external) d - W =0.25 mm (when cutting with a UV laser, the minimum width of the partition between the holes is 0.05 mm). Strip transformers are located on the board made of Rogers 5880 material and have a thickness of H =0.939 mm

Synthesis of a Luneburg lens with a flat surface using quasi-conformal transformation optics

Annotation In modern systems of radiolocation, navigation and communication, the requirements for antennas are becoming higher requirements every year, namely: operation in a wide frequency range, the ability to change of direction of the main lobe of the radiation pattern. Antenna systems with similar characteristics can be built using dielectric antenna beamforming structures. One of these structures is the Luneberg lens, the peculiarity of which is its spherical symmetry. However, the curved surface of this lens significantly complicates the placement of transmitting and receiving elements along it, which increases the complexity of constructing the entire antenna system. This paper proposes an algorithm for constructing a Luneberg lens with a flat surface. The lens was synthesized using the method of quasi-conformal optical transformations, the mathematical algorithm of which is also described in this work. The paper also presents the results of mathematical modeling of the antenna system using a Luneberg lens with a flat surface at different positions of the emitter relative to the center of the lens, as well as different cut angles. The simulation results show that the synthesized lens can be used to construct a multi-beam antenna system that allows the direction of the main lobe of the antenna radiation pattern to be rearranged over a wide range of angles. However, the scanning angles of this system are limited by the lens geometry, the larger the maximum scanning angle we choose, the more significant the influence of the side lobes on the radiation pattern becomes.

Analysis of the influence of dispersion of metamaterials in a cylindrical Luneberg lens with extended focus

Cylindrical Lunebeg lenses allow azimuthal scanning in a wide sector of angles. The article discusses a cylindrical Luneberg lens with an out-of-focus parallel printed circuit boards made of thin fiberglass (FR-4) with an etched H-shaped metamaterial structure. The distribution of the electric field in the azimuthal plane is shown when a linearly polarized plane wave is incident on the lens surface parallel to the printed circuit boards. The dependence of the focal length on the frequency is shown. Conclusions are drawn about the effect of dispersion on the focal length. To clarify the value of the focal length, thedirectional characteristics of the antenna system are considered when the focal length is changed. Directional characteristics are investigated when the feed is rotated in the azimuthal plane. The results presented in the article are planned to be used to create broadband Luneberg lenses from metamaterials.

ANTENNA SYSTEM BASED ON A FLAT LUNEBERG LENS WITH THROUGH ROUND HOLES AND AN AXISYMMETRIC TEM-HORN

Характерной чертой последних пятидесяти лет было особое стремление к постоянно растущей скорости передачи в сетях беспроводной связи. С появлением Интернета, а именно технологии (IoT), значительные усилия в сфере исследований вкладываются в беспроводные сети, требующие высокой скорости передачи и большой пропускной способности. Рассмотрена линза Люнеберга, спроектированная на заземляющей системе при помощи технологии изготовления круглых отверстий, сверху расположена диэлектрическая пластина с системой круглых отверстий, формирующая необходимый закон изменения эффективного коэффициента преломления от радиуса (материал - Rogers 5880, толщина - 0.508 мм, ). Особенностью данной конструкции являются сквозные круглые отверстия в плоской линзе Люнеберга. Минимальный диаметр отверстия - 0.4 мм; максимальный - 2.6 мм. Минимальная ширина перегородки между отверстиями - около 0.3 мм. Всего - 1295 отверстий (диаметры - 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6 мм). Показано несколько вариантов реализации данной линзы. Рассмотрено несколько вариантов того, какими должны быть отверстия в теле линзы для предпочтительного режима работы, сделаны выводы о каждом. При помощи математического, численного анализа исследована разница в случаях наличия или отсутствия «крышек» у «чашек», образующих ТЕМ-рупор в виде фигуры вращения A characteristic feature of the last fifty years has been the desire for ever-increasing transmission speeds in ubiquitous wireless communications. With the advent of the Internet, namely technology (IoT), significant research efforts are being invested in wireless networks that require high transmission speeds and increased bandwidth. In this paper, we consider a Luneberg lens designed on a grounding system using the technology of manufacturing round holes, with a dielectric plate with a system of round holes on top, forming the necessary law of change in the effective refractive index from the radius (material-Rogers 5880, thickness-0.508 mm). A special feature of this design is the through round holes in the flat Luneberg lens. The minimum hole diameter is 0.4 mm; the maximum one is 2.6 mm. The minimum width of the partition between the holes is about 0.3 mm. There are totally 1295 holes (diameters - 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6 mm). Several options for implementing this lens are shown. Several variants of what the holes in the lens body should be for the preferred mode of operation are also considered, and conclusions are drawn about each. Using mathematical and numerical analysis, the difference in the cases of the presence or absence of "lids" in the "cups" that form a TEM - horn in the form of a rotation figure is investigated

Investigation of the convergence of the integration algorithm with the choice of the variable of integration at each step using the example of a Luneberg lens

The paper describes an integration algorithm with a choice of a variable at each step in the numerical construction of ray trajectories in a medium with a given dependence of the permittivityon coordinates. The convergence of the calculations to the exact solution is estimated using the example of the problem of calculating the trajectories of rays in a Luneberg lens. It is shown that with a decrease in the grid step, convergence to the exact solution is observed. Purpose. Assess the convergence to an exact solution of an integration algorithm with a choice of a variable at each step using the example of the problem of calculating ray trajectories in a Luneberg lens. Results. The trajectories of rays incident parallel to the ordinate axis and the trajectories of rays incident at an angle to the ordinate axis are calculated. It is shown that with a decrease in the grid step, convergence of the results to the exact solution is observed. Practical significance. It is shown that an integration algorithm with a choice of a variable at each step provides the construction of ray trajectories with an error in the coordinate not exceeding the grid step for the problem of ray propagation in a Luneberg lens.

Comparative analysis of Luneberg spherical lens designs

Formulation of the problem. The development of modern mobile satellite communication systems dictates the need for the development of multipath antennas having: high values of the directional coefficient, low level of side lobes, a large number of scanning beams in a wide viewing sector without distortion in the azimuthal and angular planes. Multipath antenna systems based on spherical Luneberg lenses have these advantages. Despite their advantages, the spherical lenses of Luneberg did not find wide practical use due to the complexity of the design, the high cost of production, and the large mass (in some cases). Thanks to the progress in the field of artificial media, the emergence of new production methods, various designs of spherical Luneberg lenses have been developed. The use of artificial dielectrics allows you to create inexpensive, lightweight spherical Luneberg lenses. One widely used method of creating an artificial environment is to use partial air filling dielectrics. Luneberg lenses based on such media can have various designs: based on a dielectric ball with radial holes of variable diameter, from electrically small dielectric cubes of variable size, from a set of perforated dielectric disks, etc. For the manufacture of such lenses, various manufacturing technologies can be used, for example, three-dimensional printing, CNC machine. Purpose. Comparative analysis of the characteristics of two structures of the spherical Luneberg lens with the aim of working at frequencies above 9 GHz: from a set of perforated dielectric disks, from dielectric cubes of different sizes. Results. The results of comparative analysis of two designs of the spherical Luneberg lens are presented. The procedure of synthesis of each structure is considered. Design dependencies of effective dielectric constant used in development of investigated spherical lenses of Luneberg are given. Possible methods of technical implementation for each lens are considered, as well as important features that should be taken into account when designing and technical implementation. The weight of each structure was estimated. Conclusions about mechanical strength were made. Based on numerical modeling using the Weyland method, a comparison of directional properties in a wide frequency band was made. Conclusions have been drawn about the similarity and difference in directional characteristics. Practical importance. The scientific and technical results obtained in the article will be useful in choosing the design of the Luneberg lens from artificial dielectrics, depending on the specified technical requirements, and production conditions.