1,721,000 research outputs found
A survey of MMIC active filters
Full text linkHigh-Q filters are a critical component in many systems. However, high-Q filters require very low-loss passive elements that are not compatible with monolithic technology. Therefore, filters are often implemented as off-chip components. Tunable high-Q filters require even larger space and weight, and are usually quite bulky. Active filters have been proposed in the past for a monolithic implementation. However, it is not easy to fulfil such requirements as a high dynamic range, low power consumption, low noise, wide tunability, stability, etc. With this study, we propose a survey of the main solutions presented in the literature, investigating the fulfilment of all or most requirements and their potential applications and feasibility, to be used in practical applications
Palladium nanoparticles supported on polyvinylpyridine: catalytic activity in Heck-type reactions and XPS structural studies
No full textGaAs Balanced Amplifier for Ka-Band Space Communications System
No full textThe paper deals with the development of a state-of-the-art medium level amplifier able to combine good noise performance with a high PldB compression point. The MMIC is realized with a balanced structure and making use of the PH25 GaAs pHEMT process provided by UMS. The balanced structure allows to achieve a gain of 19 dB with a PldB compression point greater than 15 dBm and a noise figure of about 3 dB in a large bandwidth spanning from 26.5 GHz to 31.5 GHz. The chip has a single bias pad; the input and output bond wires are directly matched on chip, so easingenhancing the mechanical integration in the front-end
GaAs Balanced Amplifier for Ka-Band Space Communications System
No full textThe paper deals with the development of a state-of-the-art medium level amplifier able to combine good noise performance with a high P1dB compression point. The MMIC is realized with a balanced structure and making use of the PH25 GaAs pHEMT process provided by UMS. The balanced structure allows to achieve a gain of 19 dB with a P1dB compression point greater than 15 dBm and a noise figure of about 3 dB in a large bandwidth spanning from 26.5 GHz to 31.5 GHz. The chip has a single bias pad; the input and output bond wires are directly matched on chip, so easingenhancing the mechanical integration in the front-end
V-band low-noise amplifier module for high throughput satellite applications
No full textThis paper presents the final test results of the Low-Noise Amplifier (LNA) module developed in Thales under a contract with the European Space Agency (ESA) operating in the frequency range 47.2 to 51.6 GHz. The LNA, featuring an unsurpassed noise figure of less than 2.8dB all over the band, is a complete Engineering Model (EM), ready to be employed as a front-end in advanced Q/V band payload on board of modern High Throughput Satellites (HTS). It provides 45 dB of gain automatically compensated in temperature (range -30 to +65 °C) and high linearity, performing a third order intercept point (IP3) of 24dBm with a power consumption of 870 mW. All the MMICs composing the line-up have been fabricated in Europe by using the recently space qualified process 0.1μm GaAs PHEMT provided by UMS
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
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