Browsing by Author "Lai, Wei Yu"

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Compact Mikaelian Lens Synthesized by Metasurfaces
(2018-03-01)
Yang, Jiun Wen
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Lai, Wei Yu
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Chou, Hai Cheng
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Kehn, Malcolm Ng Mou
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電機工程學系
Synthesized using metasurfaces, we propose the implementation of the rectangular Mikaelian lens, one that is not only just flat but now also thin, thus enabling impingent wavefronts to converge at focal points over shorter distances, a feature that no other contemporary types of circularly shaped lenses are able to achieve. The subsequent savings of space and weight afforded by this unique property could be invaluable. By further postprocessing of the fields extracted from the simulations, the degree of focusing attained by the lens is also quantitatively characterized, thus offering insights beyond mere visual inspection of field patterns. The phenomenon of power concentration has been successfully demonstrated with simulations that are well corroborated by results of measurements carried out on a manufactured prototype.
Modal Analysis of Gratings With Conducting Strip-Loaded Bars and Sandwiched Between Multiple Dielectric Layers
(2020-06-01)
Kehn, Malcolm Ng Mou
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Lai, Wei Yu
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交大名義發表
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National Chiao Tung University
This communication describes a full-wave modal analysis of plane-wave scattering by periodic arrays of penetrable conducting bars with strip covers on both the lower and upper surfaces of each ridge to create iris-type slits across groove apertures, which altogether is sandwiched by multiple dielectric layers on both sides of the gratings. The approach entails the moment method using parallel-plate waveguide cavity Green's functions and a numerical spectral-domain Green's function for planar stratified media accompanied by the Floquet theorem. Computed results obtained from codes written based on this formulation are validated with those simulated by a commercial full-wave software solver as well as results from the literature. Validation is performed in terms of reflection and transmission spectra as well as modal dispersion. The new parameters arising from the special complex geometry herein studied provide the means to enhance the performances of various applications such as beam deflectors, mode converters, and grating couplers, as well as the resolution of diffraction gratings in the context of spectroscopy. Measurement results acquired from experimentations carried out on a manufactured grating that corroborate well with theoretical predictions are also presented.