Browsing by Author "Kuo, Yi-Ting"

Now showing 1 - 17 of 17

Automatic generation of passive equivalent circuits for broadband microstrip antennas
(2007)
Kuo, Yi-Ting
;
Chao, Hsueh-Yung (Robert)
;
Li, Yiming
;
電信工程研究所
;
Institute of Communications Engineering
Dual-Band Filters with Frequency-Separated Dual-Path Coupling Scheme
(2010-01-01)
Kuo, Yi-Ting
;
Lu, Jhe-Ching
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電信工程研究所
The dual-path topology is provided for dual-band filter design. The frequency-separated property is analyzed, and it shows the capability to design the filtering function separately in each path. Moreover, the dual-path topology is compatible with both symmetric and asymmetric dual-band characteristic. Two microstrip implementations are provided to demonstrate the reliability of dual-path dual-band topology.
Emission Efficiency Dependence on the Tilted Angle of Nanogaps in Surface Conduction Electron-Emitter
(2008)
Li, Yiming
;
Kuo, Yi-Ting
;
Cheng, Hui-Wen
;
Yeh, Ta-Ching
;
Lo, Hsiang-Yu
In this work, the emission efficiency of the novel surface conduction electron-emitter corresponding to tilted angles (0) of the driving electrode is studied numerically. Due to the small angle, the emitter apex becomes significant and induces large electric field. The large electric field then attracts more particles into vacuum and then increases the emission current. However, the structure of the driving electrode limits the electron trajectory while the angle decreases, and it reflects the portion of collected current by the anode decreases and makes a drop in emission efficiency. It shows there is the highest emission efficiency (about 37%) under an optimum angle theta = 60 degrees. The result provides an insight into the relation between emission efficiency and emitter apex.
Establish a six-primary color display without pixel-distortion and brightness loss
(2008-01-01)
Hsieh, Yao-Fang
;
Chuang, Ming-Chuen
;
Ou-Yang, Mang
;
Huang, Shih-Wei
;
Li, Jia Hao
Recently, color reproduction stages are developed greatly, such as liquid-crystal displays, LCD TV, LCD projectors, DLP projectors, and etc. Wide-color-gamut displays are distinguishing feature of many display manufacturers. Many researches about multi-primary color displays are proposed, but there are still some problems which are not solved. This study proposed a novel multi-primary projection display system using two projectors. One of the two projectors is modified by changing two dichroic mirrors inside. The modified projector is combined with the other to a new six-primary color display. This study applies equal-luminance boundary theorem to construct gamut volume and evaluates the merit between gamut volume and brightness. By this method, the cut-off wavelength of dichroic mirrors can be found out. In the past, to align the images of the two projectors is pre-distorted to compensate the trapezoidal distortion. This study proposes to eliminate trapezoidal distortion by using the offset of the projector. This study directly changes dichroic mirrors to maintain the brightness and contrast, and solves lower brightness and contrast resulted from adding filters before. Additionally, this study uses a reflection mirror to twist projection path and also constructs a stage to align projection images more accurately.
Low Turn-On Voltage and High Focus Capability for Field Emission Display
(2008)
Kuo, Yi-Ting
;
Lo, Hsiang-Yu
;
Li, Yiming
;
電信工程研究所
;
Institute of Communications Engineering
In this work, the properties of low turn-on voltage and high focused capability for novel field emission display are studied. According to the development of novel structure for surface conduction electron-emitter provided by Tsai et al, the 3D FTDT-PIC method has been used to analyze the properties of this device. We can find the novel structure having a tip around the corner on the left electrode implies that it can produce high electric fields around the emitter apex, and generate high emission current.
Minimal equivalent circuit extraction for high-speed PCB signal traces analysis
(2007)
Kuo, Yi-Ting
;
Chao, Hsueh-Yung
;
Li, Yiming
;
電信工程研究所
;
Institute of Communications Engineering
Integrated circuit manufacturing and packaging are important issues in realization of advanced electron devices and solid-state circuits. In this paper we develop a minimal equivalent circuit extraction technique for the high-speed PCB circuit design. Different from the conventional one, the state-space equation is constructed based on the separate set of poles instead of the common set of poles. Illustrating example is performed to show the validity of the proposed method. The extracted equivalent circuit from the proposed method has circuit components two times fewer than those form the conventional one. Furthermore, the circuit extraction takes simulation time four times faster than that of the conventional one.
Morphology effect on field emission property of carbon nanotube emitters in triode structure
(2008)
Cheng, Hui-Wen
;
Yeh, Ta-Ching
;
Kuo, Yi-Ting
;
Li, Yiming
;
Lin, Chen-Chun
In this work, process variation on the field emission property of the fabricated field emission (FE) triode arrays with carbon nanotubes (CNTs) as the field emitters are explored. To fabricate the FE triode structure, nanoporous anodic aluminum oxide (AAO) thin layer was first prepared on the Si substrate, followed by the growth of vertically aligned carbon nanotubes in AAO pore channels by electron cyclotron resonance chemical vapor deposition. The SiO2 dielectric and Al gate electrode layers required for the triode structure were directly deposited on the CNTs. Reactive ion and wet etches were then used to open the FE area in the triode. We employ the finite difference time domain particle-in-cell method to calculate the structure FE properly, where the results are calibrated with the collected FE current of the fabricated samples. The FE current Of Structure is then examined with respect to different shape, random height and angle of the CNT emitters. For symmetric shapes, like circle and square, the emission beam has been more focusing than triangle and trapezoid. The electric field of random height of CNTs is stronger than that of random angle. It is implied that the vertical CNTs has better FE property. Having the symmetric shape and vertical CNTs in triode Structure benefits the FE sources for advanced flat display technologies.
New Multiband Coupling Matrix Synthesis Technique and Its Microstrip Implementation
(2010-07-01)
Kuo, Yi-Ting
;
Lu, Jhe-Ching
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電機工程學系
In this paper, we present a novel analytical multiband transversal coupling matrix synthesis technique. By properly combining several single-band filtering functions, the multiband filtering function with flexible transmission zeros and various bandwidth are available. The transversal coupling scheme is then transformed into a practically realizable coupling scheme. To verify the feasibility of the proposed method, two dual-band coupling schemes, both single-path and dual-path, are proposed as examples of the dual-band filter design. Finally, the dual-band filter, based on the coupling matrix corresponding to a specific coupling scheme, can be realized using a microstrip parallel-coupled structure.
Novel surface conduction electron emitter (SCE) nanogaps for field emission displays
(2008)
Tsai, Chih-Hao
;
Pan, Fu-Ming
;
Lo, Hsiang-Yu
;
Li, Yiming
;
Kuo, Yi-Ting
A novel nanometer scaled gap in palladium thin film strip was prepared by hydrogen absorption under high pressure conditions, and implemented in the fabrication of the surface conduction electron emitter (SCE) for flat panel display applications. The lattice constant increase in the Pd due to the phase transformation from the a-phase to the beta-phase after hydrogen absorption, a large compressive stress occurred to the Pd thin film. With a proper geometric arrangement of the Pd/Pt/Ti emitter electrode of the SCE structure, a single nanogap per SCE device was prepared. Finite element analysis was carried out to study the hydrostatic stress distribution in the thin film emitter structure after Pd hydrogenation, and thereby the optimized thickness of thin film electrodes of the emitter Was determined for the nanogap fabrication. The novel SCE emitter had an inclined protrusion structure on the cathode, which greatly enhance the local electrical field and improve electron beam focusing. The experimental measurement and theoretical analysis show that field emission properties of the novel SCE are superior to conventional SCE with the coplanar cathode.
Optimization of physics-based equivalent circuits for microstrip patch antennas
(2007)
Chiu, Tang-Jung
;
Kuo, Yi-Ting
;
Chao, Hsueh-Yung (Robert)
;
Li, Yi-Ming
;
電信工程研究所
Optimize Maximal Brightness and Correlated Color Temperature for Multi-primary color displays
(2009-01-01)
Ou-Yang, Mang
;
Huang, Ting-Wei
;
Hsieh, Yao-Fang
;
Kuo, Yi-Ting
;
應用藝術研究所
Color temperature(CT) conversion of triprimary color display from one white point to another on the Planckian's locus with the maximal brightness has been proposed. However, whether converting an original white point to another white point on the isotemperature line will enlarge maximal brightness more than converting an original white point to another white point on the Planckian's locus needs to be determined. This paper proposes a new algorithm to enlarge maximal brightness by calling the center of gravity method of color mixing in the acceptable color difference range while the CT is converted. From the prior study, we find that the apexes of color gamut boundary move along the line of center gravity of primaries while the total brightness varies, where the line of center gravity of primaries is linked by the color points mixed by two or more full primary colors and one partial primary color. And in CIE 1931 color space, the color gamut boundary expanding from white point as total brightness decreasing will touch the isotemperature line with its apexes. Therefore, the best point of CT conversion of tri-primary color display with more maximal brightness is determined by the isotemperature line and the line of center gravity of primaries. Further, the theory extends to multi-primary color displays. Lastly, the simulations prove that converting a white point to another on the isotemperature line enlarges maximal brightness more than converting a white point to another on Planck's locus.
Research of Color Distribution Index in CIEL*a*b* Color Space
(2010)
Jeng, Wei-De
;
Huang, Ting-Wei
;
Mang Ou-Yang
;
Lee, Tsang-Hsing
;
Hsieh, Yao-Fang
The index for evaluating the ability of color reproduction is required. The color distribution index (CDI) was proposed to comment the display ability of color distribution of reproduction in CIE Lu'v' color space. A cell of Just Noticeable Difference (JND) for luminance and chromaticity (u'v') was proposed to qualify whether the reproduced colors are in some region of color volume of display. Human eye can perceive fewer colors at low luminance, however, the scalar of chromaticity (u'v') JND at low luminance was the same with the one at other luminance. CDI will be distorted at low luminance. In this paper, regarding perceptible vision at low luminance, we try to use chromaticity (a*b*) JND to replace chromaticity (u'v') JND. The color distribution will be discussed in CIE La*b* color space. We find that CDI at low luminance in CIE L*a*b* color space is higher than in CIE Lu'v' color space, as well as different gamma curves and different bit depths affect CDI. The displays are going to keep approaching 100% true color reproduction; hence the index for evaluating the ability of color reproduction is required.
Simulation-based evolutionary method in antenna design optimization for WLAN and wireless communication applications
(2007)
Li, Yiming
;
Yu, Shao-Ming
;
Kuo, Yi-Ting
;
Lie, Yih-Lang
;
電信工程研究所
In this paper, a simulation-based optimization method for the design of antenna pattern applied for mobile broadcasting and the 802.11a WLAN is presented. Based on genetic algorithm (GA), numerical simulation, and unified optimization framework, the optimization methodology is proposed for the antenna design automation. A Z-shaped antenna is optimized with respect to the return loss by our method. Inspired by the scenario of GA for optical proximity correction in our earlier work, we firstly partition the edges of the antenna into segments, and then adjust the movements of each segment to construct the geometry of new antenna. The external simulator is then called to simulate and evaluate the performance of the new antenna. If the simulated results meet the specific constraints, we output the optimized antenna. Otherwise, the evolutionary algorithms will enable us to search solution again. Our preliminary results confirm the robustness and efficiency of the proposed simulation-based optimization method.
Temperature dependence on the contact size of GeSbTe films for phase change memories
(2008-09-01)
Li, Yiming
;
Yu, Shao-Ming
;
Hwang, Chih-Hong
;
Kuo, Yi-Ting
;
資訊工程學系
In this study, a three-dimensional electro-thermal time-domain simulation is developed for dynamic thermal analysis of Phase change memories (PCMs). The geometry effects of the GeSbTe (GST) materials and the TiN heater are explored through a series of numerical examinations. It is found that the contact size of the GST significantly alters the maximum temperature of the PCMs, compared with the height of the GST films. The heater's aspect ratio also dominates the maximum temperature of the GST material, and the effect of the heater's thickness on the temperature is more evident than its height. One conformal bi-layer GST structure with different electric and thermal conductivities on the GST layers is examined for different applied currents to extract the curve of resistances versus applied currents.
Three-Dimensional Numerical Simulation of Switching Dynamics for Cylindrical-Shaped Phase Change Memory
(2008)
Li, Yiming
;
Hwang, Chih-Hong
;
Kuo, Yi-Ting
;
Cheng, Hui-Wen
;
電信工程研究所
Novel chalcogenide-based phase change memory (PCM) is a promising candidate for next-generation non-volatile solid-state memory technology for its high resistance contrast, better endurance and writing speeds than flash memory. PCM cell stores data by a thermally induced phase transition between conductive polycrystalline (set) and resistive amorphous (reset) states, in a thin film of chalcogenide materials, such as GeSbTe (GST) alloy. Therefore, the determination of the maximum temperature of GST material is crucial in design and technology of PCM. In this study, a three-dimensional electro-thermal time-domain simulation is conducted for dynamic thermal analysis of the cylindrical PCMs, where the structure GST is a cone with different cone angle, ranging from 90 degrees to 45 degrees. Our preliminary result shows the relation between contact size of GST and required programming current for GST phase transition. The GST with 90 degrees angle exhibits the smallest required programming current than the others. The angle and contact size of GST will modify the distribution of temperature and alters the maximum temperature of the GST material. This study quantitatively estimates the structure effect on phase transition of PCM and physically provides an insight into design and technology of PCMs.
Tri-Band and Quad-Band Filter Design Using E-Shaped Resonators
(2011)
Kuo, Yi-Ting
;
Li, Jian-Yu
;
Cheng, Shi-Yu
;
Chang, Chi-Yang
;
電信工程研究所
The semi-analytic procedure is provided for triband and quad-band filter design based on E-shaped resonators. With analytic synthesized procedure in dual-band filter design and connect two filters using double-diplexing configuration, the tri-band and quad-band performances can be achieved. The simulated results for the synthesized filters agree well with the ideal performances after some fine tuning. Two microstrip implementations are provided to demonstrate the reliability of tri-band and quad-band filter design.
Using Ensemble Empirical Mode Decomposition to Improve the Static Fringe Analysis in Optical Testing
(2012)
Chen, Yu-Ta
;
Mang Ou-Yang
;
Wu, Shuen-De
;
Lin, Shiou-Gwo
;
Kuo, Yi-Ting
Static fringe analysis is an important skill to reconstruct the surface profile of the tested optics. The mixed image is simulated by the tilt aberration, and several methods of the reducing mixing fringe are utilized to reconstruct the optical paths difference (OPD) profile of the mixed image. In this paper, we propose the ensemble empirical mode decomposition (EEMD) method to decompose the mixed image into several intrinsic mode functions (IMFs), and then removing one or more IMFs to reduce the influence of the mixing fringe in the mixed image. The procedure of reducing mixing fringe can reconstruct the OPD profile of the mixed image easily. In the simulation, using EEMD to reduce the influence of the mixing fringe, the root mean square (RMS) value of the OPD is 0.081 waves as the residue image subtracted from the OPD profiles of original image. In the experiment, the EEMD method reducing the noise of the mixing fringe has the advantage on the high frequency as spherical aberration.