177,275 research outputs found
Design of Gysel power combiners in E-plane rectangular waveguides
No full textThe design of 5-port power combiners using the Gysel-type architecture in full E-plane rectangular waveguide is presented. It exploits the high power handling capabilities of empty metallic waveguides and the achievable bandwidth of operation that Gysel combiners provide when compared to traditional combiners. The proposed new design takes into account the different requirements on the power handling capability of the terminating loads and their waveguide ports. This leads to having different port heights at the isolated ports, based on the need to handle certain power levels in the isolated ports in cases of phase and amplitude imbalance between inputs. The new realization is proposed in full E-plane rectangular waveguide topology for compactness, ease of fabrication, efficient full-wave analysis, and tailored power handling capabilities. A proof of concept Gysel combiner at X-band was designed, fabricated and tested, demonstrating excellent test results without any tuning: a combining loss of better than 0.5 dB over a 25% fractional bandwidth with a very compact volume of 1.2λ0 × 1.7λ0 × 1.9λ0
Compact ridge waveguide Gysel combiners for high power applications
No full text“© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works”This paper presents, to the authors´ knowledge, the first realizations of the Gysel-type power combiner/divider in ridge waveguide technology with two different configurations. Gysel combiners exhibit wider bandwidths than traditional combiners, while offering compact designs when implemented in ridge waveguide, compared with traditional waveguide combiners. In addition, Gysel combiners provide relaxed requirements on the power handling capability of the terminating loads in case of fault conditions, which may result from imbalance between the different inputs. The ridge waveguide designs offer better power handling capabilities, especially in comparison with planar designs. These advantages are shown with two different realizations, in top-bottom and side-by-side configurations, exhibiting very wide bandwidths while occupying very compact volumes. These two designs have been simulated, fabricated and tested. Excellent test results have been obtained confirming the validity of the concep
A novel compact six-pole filtering gysel combiner
No full textThis paper presents a novel two-way in-phase filtering Gysel splitter/combiner realized through a network of six-pole compact cross-coupled resonators. The network simultaneously realizes a filtering function and a two-way splitter/combiner function. Gysel combiners find application in high power amplifier designs. The five-port device uses a ring of six resonators arranged to realize, simultaneously, the combined filtering and coupling function. A rigorous coupling matrix describing the network is used to synthesize the integrated filtering and combining functions. This general network can be implemented in any of the available filter technologies. In this paper, compact combline coaxial resonators are employed and coupled using interconnected ridges to improve the bandwidth. The proposed design provides an integrated dual function module, reducing component counts and system complexity. A design was fabricated and tested demonstrating good resultsThis work was partially supported by the
Spanish Government under grant PID2020-116968RB-C32
(DEWICOM) and TED2021-130650B-C21 (ANT4CLIM)
funded by MCIN/AEI/ 10.13039/501100011033 (Agencia
Estatal de Investigacion) and by UE (European Union)
“NextGenerationEU”/PRT
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
1T memory cell based on PVDF-TrFE field effect transistor
No full textInterest in vinylidene fluoride (VDF) co-polymer with trifluorethylene (TrFE) P(VDF-TrFE) as ferroelectric material for memory application is driven by the prospect of having low cost and low operating voltage devices integrated on silicon and, at long term, migrate on flexible substrates. Some previous studies reported FET design using copolymers [1-8] but none of these structures were fully integrated on silicon wafers into a quasi-standard MOSFET fabrication process. We present for the first time the integration of a P(VDF-TrFE) (70%-30%) layer into a standard n-MOS transistor gate stack through a conventional semiconductor technology. This allows us to achieve a one-transistor (IT) Non Volatile Memory (NVM) cell. The operation voltage required for the 100nm organic ferroelectric thickness is less than 12V and a retention time ranging from few hours to few days is reported. © 2008 Materials Research Society
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
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