Antenna radome based on metal-dielectric gratings as angular filter at microwaves

2021 ◽  
Author(s):  
A.O. Kasyanov
Keyword(s):  
Antenna Arrays ◽  
Electromagnetic Compatibility ◽  
Numerical Study ◽  
Numerical Data ◽  
Microwave Antenna ◽  
Radio Electronic ◽  
Dielectric Gratings ◽  
Study Results ◽  
Frequency Selective ◽  
Metal Gratings

This article is devoted to the analysis of numerical study results of printed angular filters scattering characteristics. It is shown these angular filters may be used as antenna radomes. Numerical results are obtained by full-wave simulation of frequency-selective surfaces with dielectric covers. The numerical research results of the scattering characteristics of a printed angular filter as antenna radome based on metal-dielectric gratings are presented. A comprehensive numerical study of microwave angular filters based on multi-element multilayer printed reflect arrays has been carried out. Constructive solutions for metal-dielectric structures in integral design, realizing the functions of angular filters, are found. These solutions are based on performed numerical studies. The problems of constructive implementation of multilayer planar spatially selective as angular filters are considered. These angular filters are integrated into the radiators and feeders of modern multi-element printed phased arrays. The problems connected with creation of such arrays are also considered. The numerical simulation results for angular filters based on metal gratings with dielectric covers are obtained. These results can be used to select the most rational options for the topology of metal-dielectric gratings. Such solutions may be useful for design of multifunctional radomes in microwave antenna systems. Based on the obtained numerical data, the possibilities of using flat gratings as angular filters in the composition of antenna radomes are considered. The spatial frequency-selective structures proposed in this work are performed as multi-planar printed gratings. These gratings are designed to ensure electromagnetic compatibility of closely spaced radio electronic sets. These radio electronic sets operate in close frequency ranges. They contain antenna arrays. These arrays are placed under the antenna radomes. At the same time, the installation of angular filters in the antenna radomes makes it possible to eliminate the appearance of unwanted grating lobes in the radiation patterns of sparse antenna arrays of promising radioengineering sets at microwaves.

Frequency selective antenna radome based on metal-dielectric gratings and perforated screens

Antennas ◽  
2021 ◽  
Author(s):  
A. O. Kasyanov
Keyword(s):  
Antenna Arrays ◽  
Electromagnetic Compatibility ◽  
Numerical Study ◽  
Numerical Data ◽  
Microwave Antenna ◽  
Frequency Selective Surfaces ◽  
Radio Electronic ◽  
Dielectric Gratings ◽  
Study Results ◽  
Frequency Selective

This article is devoted to the analysis of numerical study results of printed frequency selective surfaces scattering characteristics. It has been shown that these frequency selective surfaces may be used as antenna radomes. Numerical results have been obtained by full-wave simulation of frequency-selective surfaces with dielectric covers. The numerical research results of the scattering characteristics of printed frequency selective surfaces as antenna radomes based on metal-dielectric gratings and thick perforated screens have been presented. A comprehensive numerical study of microwave frequency selective surfaces based on multi-element multilayer printed reflectarrays and thick perforated screens has been carried out. Constructive solutions for metal-dielectric structures in integral design, realizing the functions of frequency selective surfaces, have been found. These solutions are based on performed numerical studies. The problems of constructive implementation of multilayer planar spatially selective as frequency selective surfaces have been considered. These frequency selective surfaces are integrated into radiation systems of modern multi-element printed phased arrays. The problems connected with creation of such arrays have been also considered. The numerical simulation results for frequency selective surfaces based on metal gratings with dielectric covers have been obtained. These results can be used to select the most rational options for the topology of metal-dielectric gratings. Such solutions may be useful for design of multifunctional radomes in microwave antenna systems. Based on the obtained numerical data, the possibilities of using flat gratings as frequency selective surfaces in the composition of antenna radomes have been considered. The spatial frequency-selective structures proposed in this work are performed as multi-planar printed gratings. These gratings are designed to ensure electromagnetic compatibility of closely spaced radio electronic sets. These radio electronic sets operate in close frequency ranges. They contain antenna arrays. These arrays are placed under the antenna radomes.

Vibration Based Damage Detection in Plate-Like Structure Using Square of Mode Shape Curvature

2019 ◽  
Author(s):  
Ramesh Lanka ◽  
Putti Srinivasa Rao
Keyword(s):  
Mode Shape ◽  
Surface Crack ◽  
Crack Detection ◽  
Numerical Study ◽  
Numerical Data ◽  
Mode Shapes ◽  
Laser Vibrometer ◽  
Study Results ◽  
Before And After ◽  
The Impact

In this current work, a new methodology based on the square of mode shape curvature (SMSC) is presented that relates the mode shapes and its curvature changes before and after the damage for localization and sizing of the surface crack in plate-type structures. The significance of this method is it has the capability to portray accurate shape and exact location of the surface crack in a plate-like structure which are related to low and high elastic modes on dense and coarse measurement grids. The efficiency of the proposed SMSC is examined using experimental and numerical data acquired from modal analysis on the aluminum plate containing single and multi-surface cracks with a fixed-free condition using non-contact measurement a scanning laser vibrometer and on simple finite element plate model. As evidence of experimental and numerical study results, highly accurate crack characterization has been attained through the proposed method. In implementing this method, only a few modes of the structure are required. Further, the impact of the mode order on the effectiveness of crack detection, boundary distortion treatment, and grid density analysis was also performed by the proposed method.

Numerical Performances Study of Curved Photovoltaic Panel Integrated with Phase Change Material

2020 ◽  
Vol 22 (4) ◽  
pp. 1439-1452
Author(s):  
Mohamed L. Benlekkam ◽  
Driss Nehari ◽  
Habib Y. Madani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Numerical Data ◽  
Navier Stokes ◽  
Photovoltaic Panel ◽  
Pv Panel ◽  
Energy Equations ◽  
Solid Liquid ◽  
Change Material

AbstractThe temperature rise of photovoltaic’s cells deteriorates its conversion efficiency. The use of a phase change material (PCM) layer linked to a curved photovoltaic PV panel so-called PV-mirror to control its temperature elevation has been numerically studied. This numerical study was carried out to explore the effect of inner fins length on the thermal and electrical improvement of curved PV panel. So a numerical model of heat transfer with solid-liquid phase change has been developed to solve the Navier–Stokes and energy equations. The predicted results are validated with an available experimental and numerical data. Results shows that the use of fins improve the thermal load distribution presented on the upper front of PV/PCM system and maintained it under 42°C compared with another without fins and enhance the PV cells efficiency by more than 2%.

MODEL FOR ASSESSMENT OF DECISION SUPPORT APPLICATION EFFICIENCY IN RADIO-ELECTRONIC EQUIPMENT MAINTENANCE PROCESSES

2018 ◽  
pp. 66-68
Author(s):  
V. B. Tikhonov
Keyword(s):  
Electronic Equipment ◽  
Electronic Systems ◽  
Informational Support ◽  
Military Equipment ◽  
Radio Electronic ◽  
Study Results ◽  
Feasibility Evaluation ◽  
Readiness Level ◽  
Technical Operation ◽  
Maintenance Personnel

Modern radio-electronic systems (RES) of weapons and military equipment (WME) are more functionally and structurally sophisticated that results in high requirements for their effective operation organisation. Insufficient level of technical knowledge among RES WME operational and maintenance personnel often results in increase of operability restoration period of these items in case of failures. This, in its turn, results in decrease of the readiness level of the RES WME pieces. In order to reduce duration of the RES WME restoring repair in case of failures, methods and tools of the auto-mated informational support of the operational and maintenance personnel activities related to the WME operation and restoring repair are developed. This article is devoted to development of a model of the automated informational support of the personnel activities in order to find rational options of the RES WME maintenance and repair organisation. The study results related to feasibility evaluation and development of the automated technical operation system model for the radio-electronic equipment incorporated in the AD WME are provided.

A Numerical Study of Turbulent Boundary Layer Flow Over a Flat Surface With a Single Dimple

2000 ◽  
Author(s):  
Mark E. Kithcart ◽  
David E. Klett
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Flat Surface ◽  
Numerical Study ◽  
Heat Transfer Augmentation ◽  
Study Results ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

Abstract Turbulent boundary layer flow over a flat surface with a single dimple has been investigated numerically using the FLUENT CFD software package, and compared to an experiment by Ezerskii and Shekhov [1989], which studied the same configuration. The impetus for this work developed as a result of previous studies. Kithcart and Klett [1996], and Afanas’yev and Chudnovskiy [1992], showed that dimpled surfaces enhance heat transfer comparably to surfaces with protrusion roughness elements, but with a much lower drag penalty. However, the actual physical mechanisms involved in this phenomena were only partially known prior this study. Results obtained numerically are in good agreement with the experiment, most notably the confirmation of the existence of a region of enhanced heat transfer created by interaction of the flow with the dimple. In particular, the simulation indicates that heat transfer augmentation is a consequence of the development of a stagnation flow region within the dimple geometry, and the existence of coherent vortical structures which create a periodic flow-field within and immediately downstream of the dimple. This periodicity appears to govern the magnitude of the heat transfer augmentation.

Numerical study on an application of subwavelength dielectric gratings for high-sensitivity plasmonic detection

2012 ◽  
Vol 51 (20) ◽  
pp. 4722 ◽  
Author(s):  
Woo Kyung Jung ◽  
Nak-Hyeon Kim ◽  
Kyung Min Byun
Keyword(s):  
Numerical Study ◽  
High Sensitivity ◽  
Dielectric Gratings

scholarly journals Numerical Study of Hydrodynamic Impact on Bubbly Water

2015 ◽  
Author(s):  
Mehdi Elhimer ◽  
Aboulghit El Malki Alaoui ◽  
Kilian Croci ◽  
Céline Gabillet ◽  
Nicolas Jacques
Keyword(s):  
Volume Fraction ◽  
Numerical Study ◽  
Numerical Data ◽  
Void Volume Fraction ◽  
Bubbly Liquid ◽  
Impact Loads ◽  
Hydrodynamic Impact ◽  
Physical Mechanisms ◽  
The Impact ◽  
The Relationship

The phenomenon of slamming on a bubbly liquid has many occurrences in marine and costal engineering. However, experimental or numerical data on the effect of the presence of gas bubbles within the liquid on the impact loads are scarce and the related physical mechanisms are poorly understood. The aim of the present paper is to study numerically the relationship between the void volume fraction and the impact loads. For that purpose, numerical simulations of the impact of a cone on bubbly water have been performed using the finite element code ABAQUS/Explicit. The present results show the diminution of the impact loads with the increase of the void fraction. This effect appears to be related to the high compressibility of the liquid-gas mixture.

scholarly journals Adaptive algorithm based on antenna arrays for radio communication systems

2017 ◽  
Vol 14 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Valentin Fedosov ◽  
Andrey Legin ◽  
Anna Lomakina
Keyword(s):  
Wireless Networks ◽  
Antenna Arrays ◽  
Data Transmission ◽  
Communication Systems ◽  
Electromagnetic Compatibility ◽  
Signal Propagation ◽  
Time Signal ◽  
Adaptive Antenna ◽  
Spatial Coding ◽  
Multiple Input

Trends in the modern world increasingly lead to the growing popularity of wireless technologies. This is possible due to the rapid development of mobile communications, the Internet gaining high popularity, using wireless networks at enterprises, offices, buildings, etc. It requires advanced network technologies with high throughput capacity to meet the needs of users. To date, a popular destination is the development of spatial signal processing techniques allowing to increase spatial bandwidth of communication channels. The most popular method is spatial coding MIMO to increase data transmission speed which is carried out due to several spatial streams emitted by several antennas. Another advantage of this technology is the bandwidth increase to be achieved without expanding the specified frequency range. Spatial coding methods are even more attractive due to a limited frequency resource. Currently, there is an increasing use of wireless communications (for example, WiFi and WiMAX) in information transmission networks. One of the main problems of evolving wireless systems is the need to increase bandwidth and improve the quality of service (reducing the error probability). Bandwidth can be increased by expanding the bandwidth or increasing the radiated power. Nevertheless, the application of these methods has some drawbacks, due to the requirements of biological protection and electromagnetic compatibility, the increase of power and the expansion of the frequency band is limited. This problem is especially relevant in mobile (cellular) communication systems and wireless networks operating in difficult signal propagation conditions. One of the most effective ways to solve this problem is to use adaptive antenna arrays with weakly correlated antenna elements. Communication systems using such antennas are called MIMO systems (Multiple Input Multiple Output multiple input - multiple outputs). At the moment, existing MIMO-idea implementations do not always noticeably accelerate traffic at short distances from the access point, but, they are very effective at long distances. The MIMO principle allows reducing the number of errors in radio data interchange (BER) without reducing the transmission rate under conditions of multiple signal re-reflections. The work aims at developing an adaptive space-time signal algorithm for a wireless data transmission system designed to improve the efficiency of this system, as well as to study the efficiency of the algorithm to minimizing the error bit probability and maximizing the channel capacity.

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