1,720,969 research outputs found
Concentric square ring elements for dual band reflectarray antenna
No full textA preliminary study of advanced radiating elements for a dual band reflectarray antenna is presented. The resulting antenna has properties of reduced weight and thickness, and it can be employed as the ground station antenna for an ultralight UAV in the framework of a research program on a platform for emergency radio services: it can be easily mounted (stowed) on the roof of a vehicle and deployed when in operation
Prototype of a dual band reflectarray antenna for UAVs tracking
No full textPrinted reflectarray applications are significantly increasing in recent years, because they represent an ideal antenna solution, having the same radiating performances of the standard parabolic reflector, but with reduced thickness, since the reflecting surface is planar. Here, we present the preliminary analysis of a prototype dual band planar antenna, realized using the reflectarray technology. The resulting antenna is lightweight, stowable on the roof of a vehicle and easily deployable when in operation
Characterization of microstrip reflectarray square ring elements by means of an Artificial Neural Network
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Dual-band reflectarray antenna: Design and experimental validation
No full textIn this paper, we present the design and the analysis of a prototype dual band dual-layer planar reflectarray antenna with two feeds. The resulting antenna is lightweight, foldable on the roof of a vehicle and easily deployable when in operation
Optimization of a dual-band reflectarray antenna
No full textIn recent years, printed reflectarray (RA) have become more and more popular, because of their well-known advantages with respect to traditional parabolic reflectors. Their design could however be quite expensive from a computational point of view, since it requires the fulfillment of several constraints, that could be contrasting each other, and the management of many degrees of freedom, that are necessary to satisfy the design specifications. As the number of (geometrical) parameters to optimize in order to obtain the required radiating characteristics increases, their management can no longer be performed “by hand” and the use of a global optimization tool becomes almost mandatory.
Here, one of the meta-PSO (MPSO) has been applied to the optimization of a realistic structure, the dual layer reflectarray antenna with innovative radiating elements introduced for use in the base station of the WISPERS Project (Wireless Infomobility System for ultra-light Platforms for Emergency Radio Services), which deals with emergency infomobility services based on an innovative Unmanned Air Vehicle (UAV)
Optimization of a dual-layer reflectarray antenna by means of soft-computing techniques
No full textThe nature of reflectarray (RA) optimization problems is intrinsically multi-target and therefore the use of a multi-objective optimization scheme is particularly convenient, although it can be computationally expensive. In this paper some considerations on the characterization and optimization of a RA are presented. The results of the use of efficient approaches for the modeling of the planar RA or of its elementary components are introduced: all of them tend to improve the numerical efficiency of the optimization procedure, without losing in accuracy. Numerical results are provided for the optimization of a dual layer reflectarray antenna with innovative radiating elements, for use in the base station of the WISPERS Project (Wireless Infomobility System for ultra-light Platforms for Emergency Radio Services), which is based on an innovative Unmanned Air Vehicle (UAV)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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