Browsing by Author "Tsai, Po-Cheng"

Now showing 1 - 2 of 2

Compact Electromagnetic Bandgap Surfaces with Lumped Elements
(2012)
Tsai, Po-Cheng
;
Malcolm Ng Mou Kehn
;
傳播研究所
;
Institute of Communication Studies
Lumped elements connected between adjacent elements of a periodic mushroom-type electromagnetic bandgap (EBG) structure are used in a bid for strong miniaturization by pulling the EBG into the required frequency range. Since analyzing the high impedance surface structure from equivalent circuit, we can use the dispersion diagram to demonstrate the effects of tunable lumped element.
Enhancing Surface Sensitivity of Nanostructure-Based Aluminum Sensors Using Capped Dielectric Layers
(2017-10-01)
Lee, Kuang-Li
;
Tsai, Po-Cheng
;
You, Meng-Lin
;
Pan, Ming-Yang
;
Shi, Xu
The studies of nanostructure-based aluminum sensors have attracted huge attention because aluminum is a more cost-effective plasmonic material. However, the intrinsic properties of the aluminum metal, having a large imaginary part of the dielectric function and a longer electromagnetic field decay length and problems of poor long-term chemical stability, limit the surface-sensing capability and applicability of nanostructures. We propose the combination of capped aluminum nanoslits and a thin-capped dielectric layer to overcome these limitations. We show that the dielectric layer can positively enhance the wavelength sensitivities of the Wood's anomaly-dominant resonance and asymmetric Fano resonance in capped aluminum nanoslits. The maximum improvement can be reached by a factor of 3.5. Besides, there is an optimal layer thickness for the surface sensitivity because of the trade-off relationship between the refractive index sensitivity and decay length. We attribute the enhanced surface sensitivity to a reduced evanescent length, which is confirmed by the finite difference time-domain calculations. The protein-protein interaction experiments verify the high-surface sensitivity of the structures, and a limit of quantification (LOQ) of 1 pg/mL antibovine serum albumin is achieved. Such low-cost, highly sensitive aluminum-based nanostructures can benefit various sensing applications.