1,720,967 research outputs found
Design and Manufacturing of wideband buried RF feedthroughs for Wafer-level RF MEMS package
No full textThis paper reports on the design, manufacturing and RF characterization of a zero-level packaging for RF-MEMS devices based on wafer bonding technology and metal sealing ring. Coplanar buried feedthroughs have been modelled and designed for low loss and wideband RF applications. The CPW line underneath the gold ring has been tapered to compensate the
parasitic capacitance of the ring. Compensated and uncompensated packaged CPW lines have been manufactured and measured in the 0-40GHz frequency band. A significant improvement in terms of RF loss and frequency bandwidth have
been obtained thanks to the compensation procedure. Good agreement between experimental and simulated data for the capped and uncapped CPW lines have been obtained showing
minimal impact of the package on the RF performance. The RF
measurements show an average loss of 0.2 dB up to 30 GHz between packaged and unpackaged CPW lines
Combined Liquid Crystal and MEMS Phase Shifter: Preliminary Measurement Results
No full textThis paper presents preliminary measurement results of a reflection phase shifter realized in a hybrid MEMS and Liquid Crystal technology. The MEMS switch part of the phase shifter is undesirably affected by Liquid Crystal, leading to a higher actuation voltage and the absence
of a sudden switching operation. Nevertheless, measurements of the LC filled MEMS switch could achieve the desired 180° phase shift
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Development of different K-band integrated MEMS phase shifters for satellite COTM terminals
No full textThis work presents the design, manufacturing and testing of three 5-bit K-band MEMS phase shifters based on similar architectures (combination of switched line and loaded line) but employing different MEMS switch typologies (cantilevers & air-bridges) and RF junctions (SP2T & SP4T). All devices have been monolithically manufactured on 200 μm thick high resistivity silicon substrate (4”) by using the FBK MEMS process. The performance of the different devices have been compared in order to identify the best configuration to be implemented in electronically steerable phased arrays antennas for satellite COTM (communication on the move) terminals. Excellent performances were measured for the dielectric-free pad MEMS switches as well as the single bits constituting the phase shifter. The three 5-bit devices show return loss better than 15 dB for all states, with average insertion loss of 3.5 dB for the clamped-clamped, SP2T-based design, 2.2 dB for the cantilever, SP2T-based device and 2.1 dB for the cantilever, SP4T-based design. The measurements of the packaged devices are on-going
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