1,721,175 research outputs found
Microwave components realized by additive manufacturing techniques
No full textThis paper presents an overview of the use of additive manufacturing (AM) technologies for the implementation of microwave components. Two major technological solutions, based on the AM of plastic materials, are discussed: in the former case, the AM plastic is used as a dielectric material that constitutes the component. Conversely, in the latter case, the plastic material is a mere support of the metallization, thus avoiding the contact of the AM plastic with the electromagnetic field and reducing losses. Several examples are illustrated and discussed, to highlight benefits and limitations of AM techniques in the current scenario of microwave applications
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Increasing Efficiency of Leaky-Wave Antenna by Using Substrate Integrated Slab Waveguide
No full textThis letter presents a possibility of increasing the radiation efficiency of double-sided leaky-wave antennas (LWAs) by using the substrate integrated slab waveguide (SISW). The idea originates from the fact that double-sided LWAs usually operate on the second mode, and the attenuation constant of the second mode in the SISW is smaller than that in the standard substrate integrated waveguide (SIW). This inherently leads to an increase of antenna radiation efficiency, as less power is dissipated by the traveling wave. In order to prove this concept, two antennas have been designed with the same characteristics (central frequency of 28 GHz, pointing angle of 50°, and beamwidth of 10°), one based on SIW and the other based on SISW. Our experimental verification yields 64% radiation efficiency for the SIW LWA and 80% radiation efficiency for the SISW LWA, thus proving the theoretical and simulated predictions
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Sull'importanza delle indagini strumentali integrate negli angiomi sottocutanei: a proposito di un caso
No full textCompact SIW filters with transmission zeros: A review and current trends
No full textThis paper presents a review of the recent advances in the field of substrate integrated waveguide (SIW) filters, with particular emphasis on the techniques adopted to increase the out-of-band rejection of the filters and on the miniaturization strategies. After an overview of classical approaches to introduce transmission zeros in SIW filters, a number of recently introduced techniques are presented. In particular, the use of specially implemented extracted-poles topologies and of pre-filters is described, discussed, and compared. For each of these techniques, numerical and experimental results are reported for validation
Mode Matching Analysis of Waveguide Components Exploiting the Variational Meshless Method
No full textThis letter presents the analysis of waveguide components comprising a cascade of step junctions by mode matching in conjunction with the variational meshless method (VMM). In particular, a large number of modal fields of the waveguides are calculated very efficiently by the VMM. Moreover, the collocation points are randomly distributed in each waveguide cross section, and the coupling coefficients are obtained regardless of their mutual distribution. The presented technique is validated through the analysis of two junctions reported in the literature and by comparison with an finite element method (FEM) full-wave software
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