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Showing 1 to 9 of 9 for “"Archimedean Spiral"”.
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Analysis, design, and fabrication of Archimedean spiral antennas
… Here, wideband antennas are discussed and Archimedean spiral antennas are found to be appropriate elements for use in a new type of wideband array referred to as the wideband switched array. The design of an Archimedean spiral and a necessary wideband balun transformer feed structure are …
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Archimedean spiral antenna embedded with frequency selective surface for wideband applications
… antenna ranging from 3.1 GHz to 10.6 GHz. An Archimedean spiral antenna is the most potential candidate in the above mentioned applications as the antenna meets most of the above requirements. However, the practical implementation of spiral antenna is challenged by its bidirectional patterns, …
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Modeling of Spiral Waves Arising in Atrial Fibrillation
The objective of this study is to model spirals arising in atrial fibrillation. Spiral wave fronts, known to cardiologists as cardiac rotors, are responsible for heart arrhythmias. The modeling of the path of the spiral will ultimately assist in understanding why arrhythmias occur and how to treat …
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Wideband planar array antennas: theory and measurements
… on wide bandwidth planar array design. An Archimedean spiral is suggested for the array element and a model for the element radiation pattern is presented. A wide bandwidth linear array is then analyzed using the element model. The array is made to operate over a two octave bandwidth by …
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Design and Analysis of Star Spiral with Application to Wideband Arrays with Variable Element Sizes
… dissertation details the development of the star spiral antenna and demonstrates the advantages of the star spiral when used in a wideband array with variable element sizes. The wideband array with variable element sizes (WAVES) is a multi-octave array that uses different sized circular …
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Parkinson's Disease Automated Hand Tremor Analysis from Spiral Images
… tremor symptoms in Parkinson’s patients from the Archimedean Spiral test, a paper-and-pencil test used to evaluate hand tremors. This work presents a novel Fourier Domain analysis technique that transforms the pencil content of hand-drawn spiral images into frequency features. Our technique is …
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A characteristic mode perturbation approach for antenna loading design
… is used to design the reactive loading of an Archimedean spiral antenna to produce beam tilt or an endfire radiation pattern while maintaining desirable VSWR properties. Finally, the perturbation approach is used to analyze antenna loss and is applied to the analysis and improvement of antenna …
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Resonant sensors for passive, real-time, and wireless characterization of biological analytes
… The patterns of the resonators, which are Archimedean spirals, are drawn on these substrates using an indelible marker with an XY plotter. These substrates are etched with a solution containing hydrogen peroxide and hydrochloric acid in order to remove the undesired copper.</p> <p>The …
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Dynamics of confined chemical gardens and implications for submarine methane hydrates
… structure, forming a new pattern resembling an Archimedean spiral. The effective density of the precipitate as well as the permeability of the membrane were estimated from the results. Finally, in a fourth study, these findings were applied to geological fluid and venting systems of methane. The …