scholarly journals Beam Splitting Planar Inverted F Antenna For 5G Communication

2021 ◽  
Vol 71 (6) ◽  
pp. 791-797
Author(s):  
Akhilesh Verma ◽  
Raghava Nallanthighal Srinivasa

A planar inverted-F antenna with symmetrical split beams and loaded with radio frequency absorbers (here Eccosorb MCS) for 5G communication is proposed. The multi-beam antennas reduce the requirement of number of antennas and provide wide coverage. But they require a complex system such as a phased array or MIMO antennas. On the other hand, multi-beam antennas do not have such requirements. In this work, we propose a PIFA antenna which achieves multi-beam behaviour by six slabs of absorbers placed periodically between the PIFA patch and substrate to split the beams into two directions at +26°. The proposed antenna obtains a frequency band of 24.2- 25.7 GHz and achieves a high gain of approximately 10 dB at +26°. The performance of the proposed antenna is suitable for G communication. All simulations of the antenna are carried out using Ansys HFSS. The design was validated by simulations and later confirmed with measurements.  

Author(s):  
Paul Van Geert ◽  
Henderien Steenbeek

The notion of complexity — as in “education is a complex system” — has two different meanings. On the one hand, there is the epistemic connotation, with “Complex” meaning “difficult to understand, hard to control”. On the other hand, complex has a technical meaning, referring to systems composed of many interacting components, the interactions of which lead to self organization and emergence. For agents, participating in a complex system such as education, it is important that they can reduce the epistemic complexity of the system, in order to allow them to understand the system, to accomplish their goals and to evaluate the results of their activities. We argue that understanding, accomplishing and evaluation requires the creation of simplex systems, which are praxis-based forms of representing complexity. Agents participating in the complex system may have different kinds of simplex systems governing their understanding and praxis. In this article, we focus on three communities of agents in education — educators, researchers and policymakers — and discuss characteristic features of their simplex systems. In particular, we focus on the simplex system of educational researchers, and we discuss interactions — including conflicts or incompatibilities — between their simplex systems and those of educators and policymakers. By making some of the underlying features of the educational researchers’ simplex systems more explicit – including the underlying notion of causality and the use of variability as a source of knowledge — we hope to contribute to clarifying some of the hidden conflicts between simplex systems of the communities participating in the complex system of education.


Author(s):  
Nemai Chandra Karmakar

Various smart antennas developed for automatic radio frequency identification (RFID) readers are presented. The main smart antennas types of RFID readers are switched beam, phased array, adaptive beamfsorming and multiple input multiple output (MIMO) antennas. New development in the millimeter wave frequency band?60 GHz and above? exploits micro-electromechanical system (MEMS) devices and nano-components. Realizing the important of RFID applications in the 900 MHz frequency band, a 3×2-element planar phased array antenna has been designed in a compact package at Monash University. The antenna covers 860-960 GHz frequency band with more than 10 dB input return loss, 12 dBi broadside gain and up to 40° elevation beam scanning with a 4-bit reflection type phase shifter array. Once implemented in the mass market, RFID smart antennas will contribute tremendously in the areas of RFID tag reading rates, collision mitigation, location finding of items and capacity improvement of the RFID system.


Diachronica ◽  
1994 ◽  
Vol 11 (2) ◽  
pp. 157-170 ◽  
Author(s):  
Alexis Manaster-Ramer

SUMMARY Among the weakest points of Illic-Svityd's reconstruction of Nostratic is the complex system of affricates, which in Indo-European are supposed to yield *st, *sk, *skw, and *sky clusters. In what is one of the few substantive critiques of the Nostratic hypothesis, Doerfer (1973) took the proposed direction of change from affricates to clusters as a reductio ab absurdum. However, many Kartvelian specialists assume a parallel shift from affricates to clusters in most languages of this family. If we accept this, then Illic-Svitye's proposals for Nostratic and Indo-European find a precedent. On the other hand, it seems more likely that Proto-Kartvelian had clusters, which simplified to affricates in one language. And by the same token, it is possible that Nostratic had clusters instead of the affricates reconstructed by Illic-Svityc. These clusters are in certain cases preserved not only in Indo-European but also in most Kartvelian languages, whereas all other Nostratic languages have affricates. RÉSUMÉ La reconstruction du 'nostratique' d'lllic-Svityc compte parmi ses plus grandes faiblesses un systeme complexe de consonnes affriquees qui, grandes faiblesses un systeme complexe de consonnes affriquees qui, selon lui, seraient devenues les groupes consonnantiques *st, *sk, *skw et *sky en indo-europeen. Doerfer (1973), dans une des rares critiques concretes de l'hypo-these nostratique, qualifia de reductio ab absurdum une telle directionalite de changement, c'est-à-dire, la transformation d'affriqees en groupes consonnantiques. Cependant, de nombreux specialistes ont propose un changement phonologique tout a fait semblable pour la plupart des langues kartveliennes. En acceptant leur supposition, on retrouve donc un cas precédent pour la théorie phonologique d'lllie-Svitye concernant le nostratique et l'indo-euro-péen. D'un autre coté, il parait plus probable que la langue proto-karvelienne avait dék des groupes consonnantiques et que ceux-ci se soient transformé en affriquées dans Tune des ses langues derivatives. Pareillement, il est possible que la langue nostratique avait aussi des groupes consonnantiques au lieu des affriqu6es reconstruites par Illié-Svityc. Dans certains cas, ces groupes consonnantiques ont ete preserves, non seulement en indo-europeen mais aussi dans la majorité des langues kartveliennes, tandis que toutes les autres langues nostratiques ont des affriquees. ZUSAMMENFASSUNG Einer der schwachsten Punkten in Illic-Svityds Rekonstruktion des Nostra-tischen betrifft das komplexe System der Affrikaten, die im Indoeuropeaischen *st, *sk, *skw und *sky-Verbindungen ergeben sollen. Doerfer (1973), eine der wenigen substantiellen Kritiken der nostratischen Hypothese, sah in der dort angenommenen Richtung des Wandels von Affrikaten zu solchen Konso-nantenverbindungen eine reductio ab absurdwn. Indes gehen viele Spezialisten des Kartwelischen davon aus, daB in fast alien Sprachen dieser Familie ein solcher Wandel von Affrikaten zu diesen Verbindungen stattgefunden habe. Wenn wir also Illic-Svitycs Vorschlage für das Nostratische und das Indo-europeaische annehmen, dann hatten wir hier einen Praszendenzfall. Dagegen scheint es eher wahrscheinlich, daB das Proto-Kartwelische Konsonantenver-bindungen hatte, die in einer Sprache zu Affrikaten vereinfacht wurden. Eben-so ware es denkbar, daB das Nostratische solche Konsonantenverbindungen anstelle der von Illic-Svitye rekonstruierten Affrikaten hatte. Diese Verbindungen sind in der Tat in verschiedenen Fallen nicht nur im Indoeuropeaischen sondern auch in den meisten kartwelischen Sprachen erhalten, wahrend alle ubrigen nostratischen Sprachen Affrikaten haben.


2016 ◽  
Vol 19 (2) ◽  
Author(s):  
Nancy T. de Grummond

AbstractRecent scholarship on the Etruscans has produced important new insights into their practices of divination of the future by means of thunder and lightning. Not much attention has yet been given to how radically different these two natural phenomena were from the point of view of the systems that framed them and accordingly how different the appropriate rituals were. There was a highly complex system of interpreting lightning, based on the idea that there were nine Etruscan gods who could cast a bolt, and that even when one god wanted to do so, it often involved negotiations with others. It was very important for a diviner to know from which section of the sky the lightning originated and to have a full knowledge of its physical details and meanings. Thunder, on the other hand, was only a sound, and it was difficult to tell where it might have originated. Because it did not cause damage, it was seemingly not as dire as lightning. There does not seem to be a specific statement on which Etruscan deities might cause thunder, and so the diviner did not address the issue of which gods needed to be appeased. Instead, as far as we now know, thunder was judged by the day on which it was heard, and divination was thus carried out through calendrical reference, which did not require the kind of detailed training implied by the surviving texts on lightning. Since lightning is a visible phenomenon, it is not surprising that there are numerous depictions of it recognized in Etruscan mythological art. But while such examples may be duly noted, it is here argued that some images previously interpreted as lightning bolts are actually representations of thunder. A close look shows that, like the disciplines, the depictions of lightning and thunder are quite different from one another.


Author(s):  
Sandy Tyndale-Biscoe ◽  
Antonio Vallecillo ◽  
Bryan Wood

RM-ODP is a standard defining a framework for the specification of large distributed systems that is based on solid foundations, and that defines five generic and complementary viewpoints for structuring the system specifications in order to deal with their inherent complexity. One of these viewpoints, the enterprise viewpoint, focuses on the purpose, scope and policies for the system and its environment. This viewpoint is independent from any computational and platform-specific concerns, and provides a well-defined approach to enterprise modelling. However, the fact that RM-ODP does not define any notation for describing its viewpoint languages has traditionally hampered its wide adoption by many industrial sectors. On the other hand, UML is a widely accepted notation for system specification, but lacks formal semantics and has limited structuring mechanisms for dealing with large and complex system specifications. In this paper we describe how ODP and UML can be combined for enterprise modelling, showing how enterprise viewpoint specifications can be written in UML to obtain the major benefits of both approaches. The work described here is part of an ISO/IEC and ITU-T initiative to define the use of UML for ODP system specifications.


Author(s):  
Nemai Chandra Karmakar

Various smart antennas developed for automatic radio frequency identification (RFID) readers are presented. The main smart antennas types of RFID readers are switched beam, phased array, adaptive beams forming and multiple input multiple output (MIMO) antennas. New development in the millimeter wave frequency band?60 GHz and above? exploits micro-electromechanical system (MEMS) devices and nano-components. Realizing the important of RFID applications in the 900 MHz frequency band, a 3×2-element planar phased array antenna has been designed in a compact package at Monash University. The antenna covers 860-960 GHz frequency band with more than 10 dB input return loss, 12 dBi broadside gain and up to 40° elevation beam scanning with a 4-bit reflection type phase shifter array. Once implemented in the mass market, RFID smart antennas will contribute tremendously in the areas of RFID tag reading rates, collision mitigation, location finding of items and capacity improvement of the RFID system.


After a presentation of the cereal activities in Tunisia, we present, according to a systemic analysis approach, the cereal grading system. A model describing the functioning of complex system was established and has allowed identifying the information that ruled it. An information matrix is defined and elaborated, it enables on the one hand to identify the produced and consumed information concerning each activity and on the other hand to determine the relations between the activities.


Author(s):  
Achille Fumtchum* ◽  
Pierre Tsafack ◽  
Emmanuel Tanyi ◽  
Florin Hutu ◽  
Guillaume Villemaud

The aim of this work is, on one hand, to review the state of the art of the architectures and diodes used in radio-frequency energy harvesting systems, the idea here is to review the most recent works, as well as their characteristics, which include frequency, type of diode used, topology, maximum efficiency and corresponding power, and on the other hand to carry out simulations to determine the most appropriate case for any further work in the field. After having determined the most common topologies, we used the main known radio-frequency diodes to characterize them in a first step, clearly a process of comparing the results of the simulations of the different topologies is done by initially considering an identical frequency. and afterward determine the effect of frequency band on their conversion efficiency.


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


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