Browsing by Author "Wu, CK"

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Compressed-width leaky EH1 mode PBG antenna
(2003-08-01)
Wu, CK
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Chen, YC
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Tzuang, CKC
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傳播研究所
;
Institute of Communication Studies
The recently developed electric-magnetic-electric (EME) microstrip is successfully used to design a compact leaky-mode antenna with fan beam radiation patterns. The EME microstrip consists of composite metals paralleling the electric and magnetic surfaces, where the magnetic surface is made of an array of coupled inductors. The frequency scanning behavior, experimentally and theoretically confirmed by matrix-pencil analyses, indicates that the line width can be reduced by 20%, compared to that of the conventional microstrip with the identical radiation angle of the first higher order (EH1) mode at the same frequency.
Design and implementation of fault-tolerant and cost effective crossbar switches for multiprocessor systems
(1999-01-01)
Wang, K
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Wu, CK
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資訊工程學系
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Department of Computer Science
Two general crossbar switch models are proposed: the modified one-sided crossbar switch and the ripple K one-sided crossbar switch. They both balance cost and reliability, where cost is expressed in terms of crosspoint count or area. The two-sided crossbar switch and the one-sided crossbar switch are two cases of these structures. These structures provide choices for compromising structures between the two-sided crossbar switch and the one-sided crossbar switch. The effective bandwidths of these four crossbar switches are simulated. Simulation with VHDL has been performed to verify the functionality of each crossbar system. Synthesis has also been conducted to evaluate delay and area for each crossbar design. Experimental results demonstrate that the two general models of crossbar switches are cost-effective in terms of reliability and crosspoint count (or area) without reducing their effective bandwidths. The work promotes the use of the crossbar switch as an interconnection network for multiprocessor systems to enhance system performance and reliability with low cost.
Dispersion characteristics of EME microstrip at first higher order
(2002)
Wu, CK
;
Chen, YC
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Tzuang, CKC
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電信工程研究所
;
Institute of Communications Engineering
The dispersion characteristics of the electric-magnetic-electric (EME) microstrip at the first higher order are presented. The EME microstrip consists of composite metals paralleling the electric and magnetic surfaces, where the magnetic surface is made of an array of coupled inductors. The dispersion curves obtained by matrix-pencil analyses are validated experimentally by the measured radiation patterns. The line width is reduced by 47.5%, compared to that of the conventional microstrip for the same onset frequency of the leaky mode. The EME microstrip is potentially useful for compact microstrip leaky-mode array design.
Dual-frequency electric-magnetic-electric microstrip leaky-mode-antenna of a single fan beam
(2002-12-01)
Chen, YC
;
Wu, CK
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Tzuang, CKC
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a dual-frequency electric-magnetic-electric (EME) microstrip exhibiting two leaky-wave regions of similar radiation characteristics like the microstrip EH1 mode. The EME microstrip incorporates a photonic bandgap (PBG) structure, which is a two-dimensional array consisting of unit cell made of coupled coils connected by a via. The PBG structure employed in the EME prototype conducts at dc and shows the first stopband between 8.8-12.4 GHz, thus rendering the so-called magnetic surface. The EME microstrip is essentially made by substituting the PBG cells for the metal strip of a conventional microstrip. The finite-element method (FEM) analyses of the PBG structure show that the first and second modes are TM-like and TEM-like, respectively. The latter is leaky between 12.4-12.9 GHz and is found to be responsible for the second leaky region of the EME microstrip. The dispersion characteristics of the EME microstrip are obtained by two theoretical methods, name, the matrix-pencil method and the FEM. Both show excellent agreement in the two leaky regions. Furthermore, the measured far-field radiation patterns of the two leaky regions also valid ate the dispersion curves. The first leaky region is of EH, type and between 5.05-5.45 GHz. The second leaky region radiates a frequency-scanning fan beam between 11.95-13.0 GHz, similar to those of the EH, mode. Detailed modal current analyses show even and odd symmetry along longitudinal and transverse plane of EME microstrip, respectively, further confirming the two leaky regions behave like the well-known EH1 leaky mode. The proposed EME microstrip enriches the modal characteristics of the conventional, uniform microstrip and is thus a manifestation of application of PBG structure for new guiding device.
Electric-magnetic-electric slow-wave microstrip line and bandpass filter of compressed size
(2002-08-01)
Wu, CK
;
Wu, HS
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Tzuang, CKC
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電信工程研究所
;
Institute of Communications Engineering
This paper presents a novel integrated microstrip low-loss slow-wave line. The new microstrip replaces the conventional metal strip by composite metals paralleling the electric surface and magnetic surface (MS). The MS made of an array of coupled inductors shows a high-impedance state in the stopband, below which the propagation properties can be well controlled by varying the dimensions of the electric surface and MS. The dispersion curves obtained by matrix-pencil analyses closely correspond to those obtained by scattering-parameter extraction. Theoretical results, as confirmed experimentally, indicate that an increase of over 60% in the slow-wave factor can be achieved without sacrificing propagation losses, using the proposed structure. This electric-magnetic-electric (EME) microstrip is insensitive to the alignment position of the periodical structure, and can be constructed using conventional printed-circuit-board fabrication processes and integrated with other microwave components in a multilayered circuit. A compact EME bandpass filter (BPF) with suppressed harmonic responses is presented. The length of the filter is reduced by 26%, and the measured insertion loss and fractional bandwidth is comparable to that of a conventional microstrip BPF on the same substrate.
Full current-mode techniques for high-speed CMOS SRAMs
(2002)
Wang, SM
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Wu, CK
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交大名義發表
;
National Chiao Tung University
This paper describes an experimental 32Kx8 CMOS SRAM with a 9ns access time at a supply voltage of 3V using a 0.35um 1P2M CMOS logic technology. Based on the full current-mode techniques for read/write operation, the sensing speed and write pulse width are insensitive to the bit-line capacitance. Due to these techniques, the voltage swing at the bit-line and data-line can be kept quite small all the time. The active current is 28mA at 100MHz under typical conditions.
Improving the quality of liquid-crystal projection image by multilevel diffractive grating technique
(1999-07-01)
Ko, FJ
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Wu, CK
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King, HJ
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Wu, SY
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Shieh, HPD
A technique using multilevel diffractive gratings to suppress the discrete nature of liquid crystal display (LCD) projection images is demonstrated. The multilevel diffractive gratings, having a cross section similar to a staircase, are fabricated by VLSI processes and plastic molding. Upon positioning the diffractive gratings on the front surface of the LCD panel, the output light beams emitted from each pixel are diffracted mainly into the zeroth and the +/-first diffraction order light beams of equal energy. The light beams transformed by the diffractive gratings into orders higher than zeroth are able to fill up the dead space between each subpixel, and generate an array of images from each subpixel. As a result, the spatial frequency of the color subpixel distribution within the whole image is increased. Accordingly, the grain-like pixel structure in projection images is removed, at a slight expense of image resolution.
Slow-wave propagation of microstrip consisting of Electric-Magnetic-Electric (EME) composite metal strips
(2001)
Wu, CK
;
Tzuang, CKC
;
電信工程研究所
;
Institute of Communications Engineering
A novel integrated microstrip slow-wave line is presented. The new microstrip replaces the conventional metal strip by the composite metals paralleling the electric and magnetic surfaces. The magnetic surface is made of an array of coupled inductors that perturb the modal currents periodically. The theoretical results, validated by experiment, show that more than 60% increase in the slow-wave factor while maintaining the Q-factor values can be achieved using the proposed structure.