186,149 research outputs found
Terahertz disk resonator on a substrateless dielectric waveguide platform
No full textPublished 31 August 2023Abstract not availablePanisa Dechwechprasit, Rajour Tanyi Ako, Sharath Sriram, Christophe Fumeaux, and Withawat Withayachumnanku
Integrated disk resonator on substrateless dielectric waveguide platform for terahertz switch applications
No full textWe present a terahertz single-pole double-throw (SPDT) switch based on an integrated disk resonator for a substrateless dielectric platform made of an all-silicon-based effective medium. The switch operates based on photoexcitation by using visible light focused onto the disk resonator to turn off the resonance, thus removing coupling between two waveguides. The result shows low insertion loss of the proposed switch due to the low dissipation of the platform. The device achieves an extinction ratio of 11 dB and 1.5 GHz of terahertz bandwidth. This terahertz switch can be employed in various terahertz applications including phase shifting and beam steering.Panisa Dechwechprasit, Christophe Fumeaux, and Withawat Withayachumnanku
Monolithically integrated mode converter from terahertz substrateless silicon guide to conductive slotline
No full textAlthough substrateless micro-scale silicon waveguides are a useful and versatile platform for terahertz waves, the fact that modal fields occupy the volume of the core limits the potential to dynamically manipulate guided waves. To address this, we introduce an aperiodic lattice structure to enable the monolithic co-integration of a Vivaldi antenna-like mode converter with a substrateless silicon waveguide. This broadband transition is experimentally confirmed to exhibit ∼2.5 dB average loss for two couplers, from 220 GHz to 330 GHz, and enables a photoexcited variable attenuator as proof-of-concept demonstration. This is an important enabling step to incorporate general-purpose dynamic reconfigurability, sensing, and modulation functionality into terahertz-range silicon-based integrated circuits, which are currently limited to primarily all-passive structures.Daniel Headland, Panisa Dechwechprasit, and Withawat Withayachumnanku
Resonant cavities based on substrateless dielectric waveguide platform for terahertz integrated systems
No full textIn the past two decades, terahertz technology has been steadily improved with a wide range of scientific studies to develop terahertz applications. Recently, a substrateless dielec-tric waveguide platform based on effective medium has been proposed. Waveguiding on this silicon-based platform can be realized with low loss and low dispersion. One important series of components for this platform includes resonant cavities of different characteristics that are crucial for terahertz integrated systems. In this article, we present one design of a disk resonator, and one design of a photonic crystal cavity based on this sub-strateless dielectric waveguide platform. These cavities operate within the frequency range of 220–330 GHz. The simulation and measurement results of these resonant cavities show a strong resonant behavior, with a resonance Q-factor that can be tuned. These cavities can be employed in various terahertz applications including sensing, switching, and modulation.Panisa Dechwechprasit, Christophe Fumeaux, Withawat Withayachumnanku
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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
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
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
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
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