scholarly journals Metamaterials for Microwave Radomes and the Concept of a Metaradome: Review of the Literature

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
E. Öziş ◽  
A. V. Osipov ◽  
T. F. Eibert
Keyword(s):  
Aerodynamic Drag ◽  
Antenna System ◽  
Antenna Design ◽  
Review Of The Literature ◽  
Open Problems ◽  
Mechanical Parts ◽  
Artificial Materials ◽  
Potential Applications ◽  
Band Pass ◽  
Frequency Behavior

A radome is an integral part of almost every antenna system, protecting antennas and antenna electronics from hostile exterior conditions (humidity, heat, cold, etc.) and nearby personnel from rotating mechanical parts of antennas and streamlining antennas to reduce aerodynamic drag and to conceal antennas from public view. Metamaterials are artificial materials with a great potential for antenna design, and many studies explore applications of metamaterials to antennas but just a few to the design of radomes. This paper discusses the possibilities that metamaterials open up in the design of microwave radomes and introduces the concept of metaradomes. The use of metamaterials can improve or correct characteristics (gain, directivity, and bandwidth) of the enclosed antenna and add new features, like band-pass frequency behavior, polarization transformations, the ability to be switched on/off, and so forth. Examples of applications of metamaterials in the design of microwave radomes available in the literature as well as potential applications, advantages, drawbacks, and still open problems are described.

scholarly journals Cubesat Antenna Analysis and Design: Are you using the right computational electromagnetic tool?

2021 ◽  
Vol 10 (2) ◽  
pp. 1-18
Author(s):  
I. Latachi ◽  
T. Rachidi ◽  
M. Karim
Keyword(s):  
Selection Process ◽  
Critical Role ◽  
Antenna System ◽  
Antenna Design ◽  
Design Processes ◽  
Analysis And Design ◽  
Trade Offs ◽  
Development Costs ◽  
Communication Links ◽  
The Right

Antenna systems play a critical role in establishing wireless communication links and sustaining remote sensing requirements for Cubesat applications. In addition to the usual antenna design requirements, Cubesat-based spacecrafts impose additional stringent constraints related to the on-board available space, power consumption and development costs. To develop optimal antenna prototypes while considering all these constraints and decrease trial and error related costs, computational electromagnetics (CEM) simulation tools are used. The accuracy of simulation results depends to a great extent on the choice of the appropriate CEM tool for the particular antenna problem to be analyzed; ergo, identifying and answering key questions about design objectives and requirements is necessary for informed decision-making throughout the selection and design processes. However, this could be quite challenging because of existing gaps both in the practitioners’ knowledge about different CEM tools capabilities, limitations, and design know-how. This is especially true for non-specialists such as students and academics involved in student driven Cubesat projects. Therefore, the rationale of this manuscript is to bridge those gaps and clarify some common misconception commonly encountered during the selection and design processes. In that regard, first, an overview of existing antenna configurations commonly used in Cubesat communications is provided. Next, antenna design general workflow is presented. Then, capabilities and limitations of different CEM solving methods are presented. After that, CEM software selection process trade-offs and possible sources of errors are discussed from a practical viewpoint. Finally, a case study of Masat-1 antenna system design is presented as practical example.

scholarly journals Evaluation of Selected Metasurfaces’ Sensitivity to Planar Geometry Distortions

2019 ◽  
Vol 10 (1) ◽  
pp. 261
Author(s):  
Przemyslaw Lopato ◽  
Michal Herbko
Keyword(s):  
Numerical Models ◽  
Plane Deformation ◽  
Planar Geometry ◽  
Geometrical Parameters ◽  
Optical Frequency ◽  
Passive Devices ◽  
Planar Structures ◽  
Artificial Materials ◽  
Potential Applications ◽  
The Impact

In the last decade, the application of metamaterials has become a very interesting way of implementing passive devices in microwave, terahertz, and optical frequency ranges. Up until now, selective filters, absorbers, polarizers, and lenses have been designed and constructed using these artificial materials, simultaneously showing the possibility for many other potential applications. Because of the simplified fabrication process, in particular, planar structures called metasurfaces (MS), are developing very fast. In the literature, there are many studies on the properties of various metasurfaces, but there are a lack of papers related to the analysis of the impact of structure deformations on their properties. In this paper, three commonly utilized structures of metasurfaces were designed for the same resonant frequency and on the same substrate. The numerical models were built and verified using the measurements of fabricated structures. During the experiment, the geometrical parameters of the metasurface cells were swept and a mechanical in-plane deformation in orthogonal directions was applied to the examined structures. Finally, sensitivity to the geometry distortions of the analyzed structures was evaluated and discussed.

Approximate analytical HVSR curve using multiple band-pass filters and potential applications

2019 ◽  
Vol 127 ◽  
pp. 105840
Author(s):  
Aleksandar Mihaylov ◽  
Hesham El Naggar ◽  
Dimitar Mihaylov ◽  
Savka Dineva
Keyword(s):  
Potential Applications ◽  
Multiple Band ◽  
Band Pass

Closed-Loop Turbulence Control: Progress and Challenges

2015 ◽  
Vol 67 (5) ◽  
Author(s):  
Steven L. Brunton ◽  
Bernd R. Noack
Keyword(s):  
Closed Loop ◽  
Response Times ◽  
Aerodynamic Drag ◽  
Model Identification ◽  
Open Loop ◽  
Mixing Enhancement ◽  
Strong Nonlinearity ◽  
Open Problems ◽  
Loop Control ◽  
Turbulence Control

Closed-loop turbulence control is a critical enabler of aerodynamic drag reduction, lift increase, mixing enhancement, and noise reduction. Current and future applications have epic proportion: cars, trucks, trains, airplanes, wind turbines, medical devices, combustion, chemical reactors, just to name a few. Methods to adaptively adjust open-loop parameters are continually improving toward shorter response times. However, control design for in-time response is challenged by strong nonlinearity, high-dimensionality, and time-delays. Recent advances in the field of model identification and system reduction, coupled with advances in control theory (robust, adaptive, and nonlinear) are driving significant progress in adaptive and in-time closed-loop control of fluid turbulence. In this review, we provide an overview of critical theoretical developments, highlighted by compelling experimental success stories. We also point to challenging open problems and propose potentially disruptive technologies of machine learning and compressive sensing.

Percolative cobalt/silicon nitride composites with tunable negative electromagnetic parameters

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 82478-82483 ◽  
Author(s):  
Zi-dong Zhang ◽  
Chuan-bing Cheng ◽  
Xu Han
Keyword(s):  
Silicon Nitride ◽  
Electromagnetic Shielding ◽  
Band Pass Filter ◽  
Electromagnetic Parameters ◽  
Pass Filter ◽  
Potential Applications ◽  
Band Pass

A 3D fishnet structure is formed in the Co/Si3N4 composites to obtain tunable negative electromagnetic parameters from 550 MHz to 1 GHz, which have potential applications in antennas, electromagnetic shielding and band-pass filter.

A Survey on Logical Control Systems

2016 ◽  
Vol 04 (01) ◽  
pp. 97-116 ◽  
Author(s):  
Daizhan Cheng ◽  
Ting Liu
Keyword(s):  
Control Systems ◽  
Dynamic Systems ◽  
Topological Structure ◽  
Mathematical Tool ◽  
Open Problems ◽  
Research Directions ◽  
Disturbance Decoupling ◽  
Logical Control ◽  
Potential Applications ◽  
Stability And Stabilization

This paper gives a comprehensive introduction to logical control systems (LCSs), including its history, the logical background, the expression, the fundamental mathematical tool, and the analyzing method. Particularly, it is emphasized on the major achievements on logical dynamic systems (LDSs) and their control theory in last few years, consisting of (i) the topological structure of LDSs; (ii) controllability, observability, stability and stabilization, disturbance decoupling, optimal control, identification of logical (control) systems; (iii) the extension of the results about Boolean systems to k-valued and mix-valued logical (control) systems. These results form the foundation of logical control system theory (LCST). In addition, the concepts, notations, and the fundamental method/tool have been formally normalized. Some current developments of LCST and its applications or potential applications are discussed in detail. Some open problems and possible research directions are introduced.

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