A novel approach to coordinate transformation in antenna design and analysis

2005 ◽  
Author(s):  
Feng-cheng Chang
Keyword(s):  
Coordinate Transformation ◽  
Antenna Design ◽  
Novel Approach

scholarly journals Novel antenna concepts via coordinate transformation

2013 ◽  
Vol 2 (1) ◽  
pp. 25 ◽  
Author(s):  
P.-H. Tichit ◽  
S. N. Burokur ◽  
X. Wu ◽  
D. Germain ◽  
A. De Lustrac
Keyword(s):  
Coordinate Transformation ◽  
Electromagnetic Waves ◽  
Near Field ◽  
Antenna Design ◽  
Electromagnetic Properties ◽  
Field Pattern ◽  
Radiation Properties ◽  
Space Coordinate ◽  
And Control ◽  
Far Field Pattern

Coordinate transformation is an emerging field which offers a powerful and unprecedented ability to manipulate and control electromagnetic waves. Using this tool, we demonstrate the design of novel antenna concepts by tailoring their radiation properties. The wave manipulation is enabled through the use of engineered dispersive composite metamaterials that realize the space coordinate transformation. Three types of antennas are considered for design: a directive, a beam steerable and a quasi-isotropic one. Numerical simulations together with experimental measurements are performed in order to validate the coordinate transformation concept. Near-field cartography and far-field pattern measurements performed on a fabricated prototype agree qualitatively with Finite Element Method (FEM) simulations. It is shown that a particular radiation pattern can be tailored at ease into a desired one by modifying the electromagnetic properties of the space around radiator. This idea opens the way to novel antenna design techniques for various application domains such as the aeronautical and transport fields.

scholarly journals Highly Directional Small-Size Antenna Designed with Homogeneous Transformation Optics

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Zuojia Wang ◽  
Lian Shen ◽  
Jun Chen ◽  
Huaping Wang ◽  
Faxin Yu ◽  
...  
Keyword(s):  
Coordinate Transformation ◽  
Regular Polygon ◽  
Virtual Space ◽  
Transformation Optics ◽  
Antenna Design ◽  
Radiation Patterns ◽  
Antenna Aperture ◽  
Material Parameters ◽  
Large Size

Achieving high directivity antenna usually requires a large size antenna aperture in traditional antenna design. Previous work shows that, with the help of metamaterials and transformation optics, a small size antenna can perform as high directivity as a large size antenna, but the material parameters are inhomogeneous and difficult to realize. In this paper, we propose a linear homogeneous coordinate transformation to design the small size antenna. Distinguishing from inhomogeneous transformation, we construct a regular polygon in virtual space and then divide it into several triangle segments. By applying linear homogeneous coordinate transformation, the antenna devices can be greatly compressed without disturbing the radiation patterns by using homogeneous metamaterial substrates. The material parameters of the antenna designed from this method are homogeneous and easy to fabricate. Square and hexagonal antenna structures are numerically demonstrated to illustrate the validity of our methodology.

Planar focusing antenna design by using coordinate transformation technology

2007 ◽  
Vol 91 (25) ◽  
pp. 253509 ◽  
Author(s):  
Fanmin Kong ◽  
Bae-Ian Wu ◽  
Jin Au Kong ◽  
Jiangtao Huangfu ◽  
Sheng Xi ◽  
...  
Keyword(s):  
Coordinate Transformation ◽  
Antenna Design

scholarly journals Fiber Positioning Test

2013 ◽  
Vol 9 (S298) ◽  
pp. 403-403
Author(s):  
Yiqiao Dong ◽  
Haotong Zhang ◽  
Zhongrui Bai ◽  
Hailong Yuan ◽  
Yajuan Lei
Keyword(s):  
Coordinate Transformation ◽  
Flux Ratio ◽  
Position Error ◽  
Orthogonal Groups ◽  
Novel Approach ◽  
Before And After ◽  
Fiber Position

AbstractWith the concern that observed flux is very sensitive upon fiber positions, we develop a novel approach measuring the error of fiber positions in this work. More specifically, we compute two orthogonal groups of the flux ratio before and after moving the fiber a few arcseconds, and correct the system coordinate transformation based on the computed fiber position error.

A novel approach to low profile scanning antenna design using reconfigurable metasurfaces

2014 ◽  
Author(s):  
Santi C. Pavone ◽  
Enrica Martini ◽  
Matteo Albani ◽  
Stefano Maci ◽  
Christian Renard ◽  
...  
Keyword(s):  
Antenna Design ◽  
Novel Approach ◽  
Low Profile ◽  
Scanning Antenna

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

2019 ◽  
Vol 476 (24) ◽  
pp. 3705-3719 ◽  
Author(s):  
Avani Vyas ◽  
Umamaheswar Duvvuri ◽  
Kirill Kiselyov
Keyword(s):  
Oxidative Stress ◽  
Head And Neck ◽  
Transcriptional Activation ◽  
Platinum Resistance ◽  
Mrna Levels ◽  
Strong Positive Correlation ◽  
Platinum Compounds ◽  
Copper Chelation ◽  
Novel Approach ◽  
Cancer Models

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors’ platinum resistance identifies novel approach to treating these tumors.

Collecting Words: A Clinical Example of a Morphology-Focused Orthographic Intervention

2020 ◽  
Vol 51 (3) ◽  
pp. 544-560 ◽  
Author(s):  
Kimberly A. Murphy ◽  
Emily A. Diehm
Keyword(s):  
Written Language ◽  
Morphological Knowledge ◽  
English Orthography ◽  
Word Level ◽  
Novel Approach ◽  
Language Pathology ◽  
The One ◽  
Critical Intervention ◽  
Reading And Spelling ◽  
Reading And Spelling Difficulties

Purpose Morphological interventions promote gains in morphological knowledge and in other oral and written language skills (e.g., phonological awareness, vocabulary, reading, and spelling), yet we have a limited understanding of critical intervention features. In this clinical focus article, we describe a relatively novel approach to teaching morphology that considers its role as the key organizing principle of English orthography. We also present a clinical example of such an intervention delivered during a summer camp at a university speech and hearing clinic. Method Graduate speech-language pathology students provided a 6-week morphology-focused orthographic intervention to children in first through fourth grade ( n = 10) who demonstrated word-level reading and spelling difficulties. The intervention focused children's attention on morphological families, teaching how morphology is interrelated with phonology and etymology in English orthography. Results Comparing pre- and posttest scores, children demonstrated improvement in reading and/or spelling abilities, with the largest gains observed in spelling affixes within polymorphemic words. Children and their caregivers reacted positively to the intervention. Therefore, data from the camp offer preliminary support for teaching morphology within the context of written words, and the intervention appears to be a feasible approach for simultaneously increasing morphological knowledge, reading, and spelling. Conclusion Children with word-level reading and spelling difficulties may benefit from a morphology-focused orthographic intervention, such as the one described here. Research on the approach is warranted, and clinicians are encouraged to explore its possible effectiveness in their practice. Supplemental Material https://doi.org/10.23641/asha.12290687

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