1,721,151 research outputs found
3-Way Doherty Power Amplifiers: Design Guidelines and MMIC Implementation at 28 GHz
Full text linkThis article presents the design strategy and the implementation of a three-way Doherty power amplifier (DPA3W) to enhance the efficiency at deep power back-off.
Theoretical design equations are derived, based on which design charts are drawn to explore the available design space, accounting for practical constraints related to the available technology and selected application. The proposed design strategy is demonstrated by the design, fabrication and experimental characterization of a three-way multistage Doherty amplifier optimized for efficiency peaks at 6 and 12 dB back-off. The amplifier is realized on the WIN Semiconductors 150 nm GaN-SiC high-electron-mobility transistor (HEMT) monolithic process at 28 GHz, targeting 5G applications. The prototype achieves saturated output power in excess of 34 dBm and power added efficiency of the order of 15% from 6 to 12 dB back-off, demonstrating competitive performance and a good agreement between simulations and measurements, thus validating the approach
Doherty Power Amplifiers for Ka-Band Satellite Downlink
Full text linkThis paper describes the design, realization and tests of different Doherty power amplifiers (DPAs) specifically conceived for Ka-band satellite downlink applications, i.e., 17.3 - 20.3 GHz. In particular, different design strategies have been explored by accounting for the possibility to combine power on-chip at either device or PA level, also exploring the parallel (current summing) and “series” (voltage summing) interconnection of elementary devices. As a result, three DPAs have been implemented on a commercial GaN HEMT process with 100 nm gate length grown on Silicon substrate. Pros and cons of these different solutions will be highlighted by presenting the main design steps and the preliminary experimental result
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
A GaN-Based MMIC Doherty power amplifier with Class F Peaking branch
Full text linkThis paper presents a novel design approach to enhance the performance of the Peaking branch of a Doherty Power Amplifier (DPA), by properly manipulating its input harmonics through a suitable nonlinear driver stage. In particular, aiming to implement a Class F harmonic termination for the final stage, a third harmonic voltage component is injected at its input with a driver, so that the phase of the third harmonic current at the output of the final stage is reversed with respect to its normal evolution, allowing a Class F design strategy for a class C biased device. The design strategy is described together with the design and experimental characterization of a prototype for X-Band application. The DPA is realized on the 120 nm gate-length GaN-on-SiC technology available at WIN Semiconductors. The MMIC provides more than 36 dBm and 40% of output power and efficiency, respectively, at 10 GHz
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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