Browsing by Author "Shih, Yi-Sen"

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Compact and Bandwidth-Enhanced Zeroth-Order Resonant Antenna
(2015-01-01)
Chi, Pei-Ling
;
Shih, Yi-Sen
;
電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
In this letter, a simple bandwidth-enhanced zeroth-order resonant (ZOR) antenna is proposed. The presented antenna is composed of two unit cells of the composite right/left-handed (CRLH) artificial structure and operates in the series resonant mode. In order to enhance the operational bandwidth, in particular, the interdigital capacitor in a unit cell was properly designed so as to reduce the quality factor of the resonator while occupying a relatively small area. Additionally, to facilitate implementation of the short-circuited boundary condition, the coplanar waveguide (CPW) was applied to develop a via-less uniplanar antenna prototype. Experimental results show that the presented ZOR antenna achieves a 10-dB bandwidth of 15.1% and a peak radiation gain of 1.62 dBi with a compact size of 0.14 lambda(o) x 0.22 lambda(o) at the operating frequency. Measured and simulated results are in good agreement.
Defects in semipolar (11(2)over-bar(2)over-bar) ZnO grown on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 substrate by pulsed laser deposition
(2013-03-27)
Tian, Jr-Sheng
;
Wu, Yue-Han
;
Peng, Chun-Yen
;
Chiu, Kun-An
;
Shih, Yi-Sen
The microstructure of semipolar (11 (2) over bar(2) over bar) ZnO deposited on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 was investigated by transmission electron microscopy. The ZnO shows an in-plane epitaxial relationship of [11 (2) over bar3](ZnO) parallel to [11 (1) over bar](LAO/LSAT) with oxygen-face sense polarity. The misfit strain along [11 (2) over bar3](ZnO) and [1 (1) over bar 00](ZnO) is relieved through the formation of misfit dislocations with the Burgers vectors b = 1/6[11 (2) over bar3](ZnO) and b = 1/3 < 1 (2) over bar 10 >(ZnO), respectively. The line defects in the semipolar ZnO are predominantly perfect dislocations, and the dislocation density decreases with increasing ZnO thickness as a result of dislocation reactions. Planar defects were observed to lie in the M-plane and extend along < 0001 >, whereas basal stacking faults were rarely found.
Growth orientations of semipolar ZnO on GaN(1 1 (2)over-bar 2)
(2014-12-15)
Shih, Yi-Sen
;
Lin, Pei-Yin
;
Chen, Jr-Yu
;
Chang, Li
;
材料科學與工程學系
On semipolar GaN(1 1 (2) over bar 2), epitaxial ZnO grown by chemical vapor deposition can form in two different semipolar orientations as evidenced by transmission electron microscopy and X-ray diffraction. One orientation relationship is shown to be ZnO(1 1 (2) over bar 2)//GaN(1 1 (2) over bar 2) and [(1) over bar 1 0 0](ZnO)//[(1) over bar 1 0 0](GaN) which is expected for ZnO growth on GaN(1 1 (2) over bar 2), while the other is a newly found relationship of ZnO((1) over bar 0 1 (1) over bar)//GaN(0 0 0 2) and [5 (7) over bar 2 (3) over bar](ZnO)//[(1) over bar 1 0 0](GaN). (C) 2014 Elsevier B.V. All rights reserved.
HRV Response of Vegetative State Patient with Music Therapy
(2011)
Lee, Yaw-Chern
;
Lei, Chun-Yang
;
Shih, Yi-Sen
;
Zhang, Wen-Chih
;
Wang, Hui-Min
This case study centered on the effects of Music Therapy (MT) on vegetative state (VS) patients for a continuous 41-day experiment with electrocardiogram (ECG) recorded. Mahler's Second Symphony was used for this MT. There are various elements in Mahler's second symphony, with string, wind, drum, and even voice; providing the subject a strong and dynamic stimulation. There are some significant changes after 14-day stimulation: both standard deviation of all normal RR intervals (SDNN) and root mean square successive differences (RMSSD) in heart rate variability of the subject increased, indicating the activity of the cardiovascular system was enhanced. Although there's only one subject in this experiment, the results are still encouraging.
Miniaturized Zeroth-Order Resonant Antenna Using Coupling-Enhanced Meandered Structure
(2013)
Shih, Yi-Sen
;
Chi, Pei-Ling
;
電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
A zeroth-order resonant (ZOR) antenna based on the coupling-enhanced meandered unit cells is presented. The proposed unit-cell prototype is able to efficiently increase both the parasitic inductance L-R and coupling capacitance CL in the series branch of its equivalent circuit model. By connecting one end of the meandered cells to the ground plane, the resulting structure with such unit cells resonates at the resonant frequency of the series LC tank in the circuit model and can be considerably miniaturized by means of effective increases in LR and CL. The proposed ZOR antenna is composed of two meandered cells, each of which occupies only 0.036 lambda(0) x 0.0834 lambda(0) at the resonant frequency. Experimental results show that our ZOR antenna provides a fractional bandwidth of 3.6% and the peak radiation gain of 1.24 dBi while requiring a noticeably compact footprint of 0.05 lambda(0) x 0.25 lambda(0) at the operating frequency.
Orientations of ZnO grown on GaN(10(1)over-bar1)
(2015-01-01)
Shih, Yi-Sen
;
Lin, Pei-Yi
;
Wei, Lin-Lung
;
Chang, Li
;
材料科學與工程學系
On semipolar GaN(10 (1) over bar1), epitaxial ZnO grown by chemical vapor deposition consists of two distinct orientations as evidenced by transmission electron microscopy and X-ray diffraction. The initially grown ZnO on GaN follows the GaN lattice with the epitaxial relationship of ZnO(10 (1) over bar1)//GaN(10 (1) over bar1) and ZnO GaN [1 (2) over bar 10](ZnO)//[1 (2) over bar 10](ZnO). The other oriented ZnO domains then grow on faceted (10 (1) over bar1) ZnO with ZnO(0002)//ZnO(10 (1) over bar1) and [(2) over bar 110](ZnO)//[1 (1) over bar0 (1) over bar](ZnO) with good coherency with the (10 (1) over bar1) -oriented grains. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Semipolar (11(2)over-bar(2)over-bar) ZnO thin films grown on LaAlO3-buffered LSAT (112) single crystals by pulsed laser deposition
(2013-04-01)
Tian, Jr-Sheng
;
Peng, Chun-Yen
;
Wang, Wei-Lin
;
Wu, Yue-Han
;
Shih, Yi-Sen
Semipolar (11 (2) over bar(2) over bar) ZnO was successfully grown on (112) LaAlO3/(LaAlO3)(0.29)(Sr2AlTaO6)(0.35) substrate by pulsed laser deposition. The epitaxial relationship is [11 (2) over bar3](ZnO)// [11 (1) over bar](LAO/LSAT) with the polar axis of [000 (1) over bar](ZnO) pointing to the surface. For ZnO films with thickness of 1.6 mu m, the threading dislocation density is similar to 1 x 10(9) cm(-2), and the density of basal stacking faults is below 1 x 10(4) cm(-1). The (11 (2) over bar(2) over bar) ZnO exhibits strong (DX)-X-0 emissions with a FWHM of 9 meV and very few green-yellow emissions in the low-temperature (10 K) and room-temperature photoluminescence spectra, respectively. The XRD 2 theta-theta pattern of 1.6 mu m ZnO films grown on (112) LaAlO3/LSAT only reveals a sharp (11 (2) over bar(2) over bar) ZnO reflection for ZnO. The inset figure is the XRD rocking curve of (11 (2) over bar(2) over bar) ZnO with a FWHM of 0.084 degrees. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
;
Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
;
Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Structural properties of Al-rich AlInN grown on c-plane GaN substrate by metal-organic chemical vapor deposition
(2014-11-23)
Lin, Pei-Yin
;
Chen, Jr-Yu
;
Shih, Yi-Sen
;
Chang, Li
;
材料科學與工程學系
The attractive prospect for AlInN/GaN-based devices for high electron mobility transistors with advanced structure relies on high-quality AlInN epilayer. In this work, we demonstrate the growth of high-quality Al-rich AlInN films deposited on c-plane GaN substrate by metal-organic chemical vapor deposition. X-ray diffraction, scanning electron microscopy, and scanning transmission electron microscopy show that the films lattice-matched with GaN can have a very smooth surface with good crystallinity and uniform distribution of Al and In in AlInN.
Twin-Peak Effect in Both Cardiac Response and Tempo of Popular Music
(2011)
Shih, Yi-Sen
;
Zhang, Wen-Chih
;
Lee, Yaw-Chern
;
Lei, Chun-Yang
;
Tseng, Cheng-Lung
How the musical tempo affects the performance of heart rate variability (HRV) was studied in this work. By understanding the relationship between the HRV response and the music tempo with decreasing tempo from 140 to 70 beats per minute (bpm) periodically in six successive weeks. There were two groups in the experiment, one was listening drum loop music 3 minutes in the middle of experiment and the other was just rest for 20 minutes. After the processed the information from the objects, the distribution of difference of HRV response between before and after listening various tempo drum loop was similar to the distribution of modern popular music in tempo. Both distributions have the twin peaks about 70-85 and 110-125 bpm.