Browsing by Author "Wang, SM"

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A study of meandered microstrip coupler with high directivity
(2003)
Wang, SM
;
Chen, CH
;
Chang, CY
;
電信工程研究所
;
Institute of Communications Engineering
A novel design technique to improve the directivity of a microstrip direction coupler by a meandered structure is proposed in this paper. Increasing of even-mode phase velocity by the proposed meandering method is reported for the first time. An analytical method to obtain closed-form equations of even-mode phase velocity is developed. The proposed structure is verified by experiments. More than 40 dB measured directivity improvement comparing to conventional microstrip coupler is achieved.
Analysis and design of a new SRAM memory cell based on vertical lambda bipolar transistor
(2003-09-01)
Wang, SM
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A voltage-controlled negative-differential-resistance device using a merged integrated circuit of two n-channel enhancement-mode MOSFETs and a vertical NPN bipolar transistor, called vertical Lambda-bipolar-transistor (VLBT), is presented for memory application. The new VLBT structure has been developed and its characteristics are derived by a simple circuit model and device physics. A novel single-sided SRAM cell based on the proposed VLBT is presented. Due to the characteristics of the VLBT, it offers better static noise margin and larger driving capability as compared with conventional single-side CMOS memory cell. (C) 2003 Elsevier Science Ltd. All rights reserved.
Bandpass filters with resistive attenuators being located at 2(nd) and 4(nd) spurious pass-bands
(2004)
Hsieh, MY
;
Wang, SM
;
Chang, CY
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, a novel resonator consisting of one half-wave transmission line and the resistive attenuator is proposed to build BPF (bandpass filter) with good stop-band suppression. The resonance characteristics of this type of resonator are intuitive through the ABCD matrix analysis. By means of utilizing the conventional design methodology for parallel coupled-line based BPF, the newly proposed filters can be easily realized by inserting attenuator in coupled-line filter. To confirm the validity of the technique, filters of orders-2 BPF centered at 2.25 GHz with a 5% FBW (Fractional Bandwidth) and orders-3 BPF centered at 2.05 GHz with a 12% FBW were used. Successfully, filters in this paper revealed the 2(nd) spurious response of at least 30 dB insertion loss.
Compact and wideband microstrip bandstop filter
(2005-07-01)
Hsieh, MY
;
Wang, SM
;
交大名義發表
;
National Chiao Tung University
A novel one-section bandstop filter (BSF), which possesses the characteristics of compact size, wide bandwidth, and low insertion loss is proposed and fabricated. This bandstop filter was constructed by using single quarter-wavelength resonator with one section of anti-coupled lines with short circuits at one end. The attenuation-poles characteristics of this type of bandstop filters are investigated through TEM transmission-line model. Design procedures are clearly presented. The 3-dB bandwidth of the first stop-band and insertion loss of the first passband of this BSF is from 2.3 GHz to 9.5 GHz and below 0.3 dB, respectively. There is good agreement between the simulated and experimental results.
Full current-mode techniques for high-speed CMOS SRAMs
(2002)
Wang, SM
;
Wu, CK
;
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.
Microstrip directional coupler with nearly ideal TEM coupler performance
(2005-05-26)
Wang, SM
;
Hsieh, MY
;
Chiang, CH
;
Chang, CY
;
電信工程研究所
A meandered parallel coupled-line structure is proposed to achieve high directivity within a wide bandwidth. By properly increasing the meandered parallel coupled-line sections, the high-directivity band-width becomes much wider. An example coupler is fabricated to verify the theory. More than 50 dB of isolation is achieved over a bandwidth of zero to twice centre frequency.
Miniaturized spurious passband suppression microstrip filter using meandered parallel coupled lines
(2005-02-01)
Wang, SM
;
Chi, CH
;
Hsieh, MY
;
Chang, CY
;
電信工程研究所
A novel meandered parallel coupled-line structure is proposed to suppress the first spurious passband of a microstrip bandpass filter. The meandered parallel coupled line can equalize the modal transmission phases at any interested frequency such as first spurious passband frequency due to its dispersive response. Several filters are designed and fabricated on a substrate with a dielectric constant of 10.2 and a thickness of 50 mil (1.27 mm) to demonstrate the validity of the proposed method. The example filters are chosen to be of large fractional bandwidth and with a relatively high dielectric-constant substrate where, in these cases, the first spurious passband near twice of the passband frequency (2f(o)) seriously degrades the conventional parallel coupled filter's upper stopband performance. The upper stopband performance of the proposed filters drastically improves that the measured first spurious passband are suppressed to better than -50 dB for all example filters. Besides, a meandered coupled line not only suppresses the filter's first passband, but also largely shrinks its length. The characteristics of the proposed structure and the design procedures of the filter are described in detail.
New high-speed low-power current-mode CMOS sense amplifier
(2003-05-01)
Wang, SM
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A novel low-power current-mode sense amplifier for fast CMOS SRAM applications is presented. It is based on the current mode approach. The sensing speed is independent of the bit-line and data-line capacitances and a separated positive feedback technique is employed to give the circuit high-speed, low-power operation. Based on the new current-mode sense amplifier, a 32Kx8 SRAM chip was designed and fabricated. The access time is 9ns at a supply voltage of 3V and the active current is 28mA at 100MHz.
The fully economic evluation for transport infrastructure project
(2005)
Feng, CM
;
Wang, SM
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
By combining with the contingent valuation method and the fully economic evaluation approach, a new model for transport project evaluation is constructed. Different from the traditional cost-benefit analysis (CBA), this new model can easily transform the non-market goods into monetary terms and incorporate them onto the evaluation process. In the empirical case of Pinling interchange, two scenarios, with and without traffic regulations, are constructed. The estimation results show that by comparing with the fully economic evaluation approach, the traditional CBA would underestimate the environment effect and cause a biased policy decision. Moreover, since the resident interest groups could gain significant benefits, they incline to form pressure groups to lobby for the regulation release. On the other hand, although the water-use interest group bears the relative high cost at aggregate level, only a slight amount is paid by the individual that explains their indifferent attitude.