Browsing by Author "Yang, Jiun Wen"

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Compact Mikaelian Lens Synthesized by Metasurfaces
(2018-03-01)
Yang, Jiun Wen
;
Lai, Wei Yu
;
Chou, Hai Cheng
;
Kehn, Malcolm Ng Mou
;
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.
Plasmonic Luneburg lens antenna synthesized by metasurfaces with hexagonal lattices
(2017-10-30)
Chen, Kuang Cheng
;
Yang, Jiun Wen
;
Yang, Yueh-Chieh
;
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