Browsing by Author "Yang, Yueh-Chieh"

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Analysis of Strip-Grated Conducting Rod Using Asymptotic Strip Boundary Conditions
(2018-01-01)
Yang, Yueh-Chieh
;
Kehn, Malcolm Ng Mou
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電信工程研究所
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Institute of Communications Engineering
In this paper, an analytical method that deals with the solutions for surface wave modes that propagate along a dielectric coated conducting cylinder loaded with a periodic array of metallic transverse strips is presented. The approach hinges on the asymptotic strip boundary conditions (ASBC) along with classical electromagnetic theory of vector potentials that dramatically simplify the formulation as compared to the use of traditional Floquet mode expansion. The method would be validated by presenting the consistency of the dispersion properties obtained from the ASBC method with those simulated by an independent full wave solver. The closed form field expressions have been derived successfully by this method.
Analysis of Strip-Grated Dielectric-Coated Rods by Asymptotic Strip Boundary Conditions for Studies of Dielectric Losses and Field Localization
(2019-05-01)
Yang, Yueh-Chieh
;
Kehn, Malcolm Ng Mou
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, the surface-wave modal analysis of the transverse strip-grated dielectric-coated metal rod is done by using the asymptotic strip boundary conditions (ASBC) along with classical vector potentials in the cylindrical coordinate system. The yielded solvable system of linear equations is then cast into a homogeneous matrix equation, from which the characteristic equation as well as field distributions in explicit functional forms may be obtained. Modal dispersion diagrams and field distributions generated by this method are compared and validated with those simulated by an independent commercial full wave solver. The time cost by the ASBC method is also compared with that of the simulation software, upon which the vast superiority in speed of the proposed technique over the benchmark tool is demonstrated, but yet preserving high accuracy. Parametric studies that portray the variations of dispersion properties with various geometric attributes are carried out. Comparisons with its counterpart transverse corrugated rod are also carried out, and studies of dielectric losses are presented as well. A prototype was fabricated and measured, the experimental results of which concur well with theoretical expectations.
Plasmonic Luneburg lens antenna synthesized by metasurfaces with hexagonal lattices
(2017-10-30)
Chen, Kuang Cheng
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Yang, Jiun Wen
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Yang, Yueh-Chieh
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Khin, Chang Fu
;
Kehn, M. Ng Mou
The metasurface lens composing of 2D periodic metallic patches on a grounded dielectric slab possesses several advantages such as being light, low-profile, compact, and also cheap to manufacture. In this paper, a Luneburg lens synthesized by a metasurface and designated for use as a surface wave antenna is proposed. Two types of unit cell will be compared, one whose surface wave modal dispersion varies significantly with the grazing direction and another that does not. In the context of being applied as surface wave antennas, it will be shown that the Luneburg lens synthesized by the latter kind of unit cell provides improved performance as compared to the former. Several aperture sub-efficiencies of the metasurface-based Luneburg-lens antenna shall be used for the characterization of the radiation. A prototype of the designed lens antenna has also been manufactured. Measurement results agree well with theoretical predictions and the efficacy of this device over a fairly wide bandwidth has been experimentally demonstrated. (C) 2017 Optical Society of America