Browsing by Author "Chen, Wei-Cheng"

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A 37.5-mW 8-dBm-EIRP 15.5 degrees-HPBW 338-GHz Terahertz Transmitter Using SoP Heterogeneous System Integration
(2015-02-01)
Li, Chun-Hsing
;
Chao, Tzu-Yuan
;
Lai, Chih-Wei
;
Chen, Wei-Cheng
;
Ko, Chun-Lin
A low-cost terahertz transmitter is proposed by using system-on-package (SoP) heterogeneous system integration. A signal source in 40-nm CMOS is integrated with an antenna array on a Benzocyclobutene carrier through a broadband low-loss terahertz interconnect. The signal source adopting triple-push oscillator topology is able to produce a differential output without any additional balun circuit. Hence, the power consumption and the chip area can be reduced. The antenna array containing 50 patch antennas is differentially excited to give simulated directivity, efficiency, and antenna gain as high as 22.6 dB, 88%, and 22 dBi, respectively, at 335 GHz. The terahertz interconnect employs a resonator coupling technique to provide low-loss and broadband performance while occupying a small area. Measured results show that the proposed terahertz transmitter can work at 338.4 GHz with equivalent isotropically radiated power (EIRP) of 8.0 dBm while consuming only 37.5 mW from a 1-V supply. The measured half-power beam-width can be as narrow as 15.5 degrees. The EIRP can be further raised to 9.5 dBm as the supply V-DD is increased to 1.3 V. The CMOS chip only occupies an area as small as 0.028 mm(2). All of the design efforts enable the proposed terahertz transmitter to feature in small form factor, low power dissipation, low cost, and high performance. To the best of the authors\' knowledge, this is the most compact, lowest power, lowest cost, and high-performance SoP-based terahertz transmitter reported thus far.
A reliability model for low-temperature polycrystalline silicon thin-film transistors
(2007-05-01)
Chen, Chih-Yang
;
Lee, Jam-Wem
;
Lee, Po-Hao
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
We proposed here a reliability model that successfully. introduces both the physical mechanisms of negative bias temperature instability (NBTI) and hot carrier stress (HCS) for p-channel low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). The proposed model is highly matched with the experimental results, in which the NBTI dominates the device reliability at small negative drain bias while the HCS dominates the degradation at large negative drain bias. In summary, the proposed model provides a comprehensive way to predict the lifetime of the p-channel LTPS TFTs, which is especially necessary for the system-on-panel circuitry design.
Analysis of negative bias temperature instability in body-tied low-temperature polycrystalline silicon thin-film transistors
(2008-02-01)
Chen, Chih-Yang
;
Ma, Ming-Wen
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
;
Yeh, Kuan-Lin
Negative bias temperature instability (NBTI) degradation mechanism in body-tied low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) is analyzed by the charge-pumping (CP) technique. The properties of bulk trap states (including interface and grain boundary trap states) are directly characterized from the CP current. The increase of the fixed oxide charges is also extracted, which has not been quantified in previous studies of NBTI degradation in LTPS TFTs. The experimental results confirm that the NBTI degradation in LTPS TFTs is caused by the generation of bulk trap states and oxide trap states.
Bias temperature instabilities for low-temperature polycrystalline silicon complementary thin-film transistors
(2007)
Chen, Chih-Yang
;
Lee, Jam-Wem
;
Ma, Ming-Wen
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
The degradation mechanisms of both negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI) were studied for low-temperature polycrystalline silicon complementary thin-film transistors. Measurements show that both NBTI and PBTI are highly bias dependent; however, the effect of the temperature is only functional on the NBTI stress. Furthermore, instead of interfacial trap-state generation during the NBTI stress, the PBTI stress passivates the interface trap states. We conclude that the diffusion-controlled electrochemical reactions dominate the NBTI degradation while charge trapping in the gate dielectric controls the PBTI degradation. (c) 2007 The Electrochemical Society.
CCN6-mediated MMP-9 activation enhances metastatic potential of human chondrosarcoma
(2018-09-20)
Tzeng, Huey-En
;
Tang, Chih-Hsin
;
Wu, Sz-Hua
;
Chen, Hsien-Te
;
Fong, Yi-Chin
Chondrosarcomas are primary malignant bone tumors that have a poor prognosis. WNT1-inducible signaling pathway protein-3 (WISP-3, also termed CCN6) belongs to the CCN family of proteins and is implicated in the regulation of various cellular functions, such as cell proliferation, differentiation, and migration. It is unknown as to whether CCN6 affects human chondrosarcoma metastasis. We show how CCN6 promotes chondrosarcoma cell migration and invasion via matrix metallopeptidase-9 (MMP)-9 expression. These effects were abolished by pretreatment of chondrosarcoma cells with PI3K, Akt, mTOR, and NE-KB inhibitors or short interfering (si)RNAs. Our investigations indicate that CCN6 facilitates metastasis through the PI3K/Akt/mTOR/NE-KB signaling pathway. CCN6 and MMP-9 expression was markedly increased in the highly migratory JJ012(S10) cell line compared with the primordial cell line (JJ012) in both in vitro and in vivo experiments. CCN6 knockdown suppressed MMP-9 production in JJ012(S10) cells and attenuated cell migration and invasion ability. Importantly, CCN6 knockdown profoundly inhibited chondrosarcoma cell metastasis to lung. Our findings reveal an important mechanism underlying CCN6-induced metastasis and they highlight the clinical significance between CCN6 and MMP-9 in regard to human chondrosarcoma. CCN6 appears to be a promising therapeutic target in chondrosarcoma metastasis.
CMOS THz Transmissive Imaging System
(2014)
Yan, Tzu-Chao
;
Li, Chun-Hsing
;
Lai, Chih-Wei
;
Chen, Wei-Cheng
;
Chao, Tzu-Yuan
This paper presents a THz imaging system composed of a signal source and a signal sensor in CMOS technology The signal source integrates a 338 GHz oscillator in 40-nm CMOS and an antenna array on a Benzocyclobutene (BCB) carrier using the SoP (System-on-Package) technique. The measured EIRP achieves +8 dBm. The signal sensor is implemented in 0.18 mu m CMOS. The measured maximum responsivity is 632 kV/W at 332 GHz. The signal source and signal sensor consume dc power of 37.5 mW and 7.92 mW, respectively. The resolution of the proposed THz imaging system is 4 mm.
Current Sensorless Control for Dual-Boost Half-Bridge PFC Converter
(2015)
Lu, Che-Yu
;
Chen, Hung-Chi
;
Chen, Wei-Cheng
;
Li, Chung-Yi
;
電機學院
In this paper, the current sensorless control for dual-boost half-bridge (DBHB) converter with power factor correction (PFC) function is presented. The short-through problem can be avoided by the dual-boost structure for enhancing the reliability. It also reduces the power dissipation due to the body diodes\' reverse recovery current of switches. Furthermore, the intrinsic voltage-doubler characteristic of half-bridge structure is often used in high voltage application. The conventional multiloop control needs many voltage and current feedback signals. In order to simply the control loops and reduce the number of sensors, the feasibility of current sensorless control strategy should be evaluated. Therefore, the electrical characteristics of the proposed current sensorless control scheme are completely analyzed in this paper. At last, some simulation and experimental results are provided to demonstrate and illustrate the performance of the proposed current sensorless control.
Digital Current Sensorless Control for Dual-Boost Half-Bridge PFC Converter With Natural Capacitor Voltage Balancing
(2017-05)
Chen, Hung-Chi
;
Lu, Che-Yu
;
Li, Guan-Ting
;
Chen, Wei-Cheng
;
電機工程學系
To improve the efficiency of the conventional boost-type power factor correction (PFC) converters with the diode bridge circuit, the PFC converters of bridgeless category are often used. Due to no series-connected switches and no short-through risks, the dual-boost half-bridge (DBHB) circuit is used as the PFC converter in this paper. In order to simplify the conventional two-loop control scheme and reduce the number of sensors, the behaviors of the DBHB PFC converter are studied and its equivalent single-switch model is developed. Then, the current sensorless control for the DBHB PFC converter is proposed to achieve voltage regulation and yield sinusoidal input current in phase with the input voltage without sensing any current. In addition, the proposed method is able to balance capacitor voltages naturally without adding any voltage balancing control loop. An 800-W DBHB PFCprototype is implemented to evaluate the control performance. Both simulation and experimental results are provided to demonstrate the proposed current sensorless control method.
Dynamic negative bias temperature instability in low-temperature poly-Si thin-film transistors
(2007)
Chen, Chih-Yang
;
Wang, Tong-Yi
;
Ma, Ming-Wen
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
Dynamic negative bias temperature instability in p-channel low-temperature poly-Si thin-film transistors was studied in this paper. The degradation of the devices was found to be voltage and temperature dependent. In addition, the frequency and duty ratio of the gate pulse affects the degree of the device degradation. The mechanism of the device degradation was investigated, and a physical model is proposed to explain the mechanism.
Electronic THz Transmissive Imaging System
(2015)
Chen, Wei-Cheng
;
Lai, Chih-Wei
;
Yan, Tzu-Chao
;
Li, Chun-Hsing
;
Chao, Tzu-Yuan
An electronic THz transmissive imaging system is presented in this work. This system is composed of a CMOS signal source, a CMOS signal sensor, lenses, and commercial electronic chopping components. The output frequency of the signal source is 339 GHz, and the responsivity of the signal sensor is 200 kV/W. The total dc power consumption of those CMOS circuits is 91.02 mW. Using electronic chopping at the frequency up to 100 kHz helps improve the system dynamic range and makes imaging feasible. The resolution of the realized imaging system achieves 2 mm.
Enhancement of CMOS THz Imaging Sensing By Packaging Technology
(2017-01-01)
Kuo, Chien-Nan
;
Chen, Wei-Cheng
;
Chiu, Te-Yen
;
Li, Chun-Hsing
;
電子工程學系及電子研究所
Terahertz imaging sensing provides numerous attractive applications in different areas, for example, biology and medicine. CMOS technology benefits an imaging system in low cost and a small form factor. The technology advance is technically viable for circuit design in such high frequencies. Lossy silicon substrate, however, still degrades system performance. We will discuss the techniques of performance enhancement.
eSES: Enhanced Simple Energy Saving for LTE HeNBs
(2017-11-01)
Lin, Yi-Bing
;
Wang, Li-Chang
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Chen, Wei-Cheng
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資訊工程學系
;
Department of Computer Science
This letter proposes enhanced simple energy saving (eSES), a simple yet novel scheme, that turns off the RF module of inactive low-power LTE Home evolved Node B (HeNBs), and accurately wakes up these dormant HeNBs when there are connection requests. The eSES does not modify the 3rd Generation Partnership Project (3GPP) specifications, and can co-exist with other HeNBs that do not exercise the eSES. We show that the eSES effectively saves the energy consumption of a dormant HeNB at the cost of moderately increasing the connection time of the first call request to the HeNB.
Optimization of light diffraction efficiency and its enhancement from a doped-PMMA volume holographic material
(2013-11-01)
Hsieh, Mei-Li
;
Chen, Wei-Cheng
;
Chen, Hong-Yu
;
Lin, Shawn-Yu
;
光電工程學系
In this paper, we study the diffraction efficiency from the volume gratings in holographic materials, PQJ PMMA, and their efficiency-enhancement in an optically dark environment (dark enhancement). We show that the diffraction efficiency is increased in real-time by light-exposure and then by a slow diffusion process in the dark after light-exposure. We observe strong correlations between the efficiency, the light-exposure energy and the dark-enhancement. Furthermore, we establish an optimum condition for light-exposure and dark-enhancement. Accordingly, we simultaneously achieve the best diffraction-efficiency of 82% for a 2 mm thick PQ/PMMA and an efficiency-enhancement of 3.1 times after exposure, approaching the theoretical limit of 4 times. Published by Elsevier B.V.
Phomaketide A Inhibits Lymphangiogenesis in Human Lymphatic Endothelial Cells
(2019-04-01)
Tai, Huai-Ching
;
Lee, Tzong-Huei
;
Tang, Chih-Hsin
;
Chen, Lei-Po
;
Chen, Wei-Cheng
Lymphangiogenesis is an important biological process associated with cancer metastasis. The development of new drugs that block lymphangiogenesis represents a promising therapeutic strategy. Marine fungus-derived compound phomaketide A, isolated from the fermented broth of Phoma sp. NTOU4195, has been reported to exhibit anti-angiogenic and anti-inflammatory effects. However, its anti-lymphangiogenic activity has not been clarified to date. In this study, we showed that phomaketide A inhibited cell growth, migration, and tube formation of lymphatic endothelial cells (LECs) without an evidence of cytotoxicity. Mechanistic investigations revealed that phomaketide A reduced LECs-induced lymphangiogenesis via vascular endothelial growth factor receptor-3 (VEGFR-3), protein kinase C (PKC), and endothelial nitric oxide synthase (eNOS) signalings. Furthermore, human proteome array analysis indicated that phomaketide A significantly enhanced the protein levels of various protease inhibitors, including cystatin A, serpin B6, tissue factor pathway inhibitor (TFPI), and tissue inhibitor matrix metalloproteinase 1 (TIMP-1). Importantly, phomaketide A impeded tumor growth and lymphangiogenesis by decreasing the expression of LYVE-1, a specific marker for lymphatic vessels, in tumor xenograft animal model. These results suggest that phomaketide A may impair lymphangiogenesis by suppressing VEGFR-3, PKC, and eNOS signaling cascades, while simultaneously activating protease inhibitors in human LECs. We document for the first time that phomaketide A inhibits lymphangiogenesis both in vitro and in vivo, which suggests that this natural product could potentially treat cancer metastasis.
Plasma-induced damage on the performance and reliability of low-temperature polycrystalline silicon thin-film transistors
(2007)
Chen, Chih-Yang
;
Wang, Shen-De
;
Shieh, Ming-Shan
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
We have investigated the impact of plasma-induced damage on the performance and reliability of low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). The LTPS TFTs having different antenna structures were used to study the effects of the plasma-etching process. We observed that performance instability occurred for the devices having a relatively large-area antenna. Plasma damage mainly caused nonuniform distribution of the threshold voltages in the LTPS TFTs, presumably because of charge trapping in the gate dielectric during the plasma-etching process. The reliabilities of the LTPS TFTs having larger antenna areas were found to be more degraded under gate-bias stress and hot-carrier stress than those of the samples having smaller antenna areas. Because of their enhanced plasma damage, we speculate that the LTPS TFTs having larger antenna areas possess more trap states in the gate dielectrics. During gate-bias stress or hot-carrier stress, therefore, charges can be injected into the gate dielectric through trap-assisted tunneling, resulting in significant degradation of both the performance and reliability. (c) 2006 The Electrochemical Society.
Process induced instability and reliability issues in low temperature poly-Si thin film transistors
(2006)
Chen, Chih-Yang
;
Wang, Shen-De
;
Shieh, Ming-Shan
;
Chen, Wei-Cheng
;
Lin, Hsiao-Yi
We investigated the impact of plasma process on the devices' performance and reliability degradation of low temperature poly-Si thin film transistors (LTPS TFTs). LTPS TFTs with different antenna areas were used to study the effects of the plasma etching process on the devices. The larger TFT antenna area, the more performance instability occurs. The reliability of LTPS TFTs with large antenna areas was found to be degraded from gate bias stress and hot carrier stress.
The Experimental Study of THz Image Sensor in 0.18 mu m CMOS Technology
(2014)
Lai, Chih-Wei
;
Chen, Wei-Cheng
;
Yan, Tzu-Chao
;
Li, Chun-Hsing
;
Kuo, Chien-Nan
In this study, four different types of power detectors are implemented in 0.18 mu m CMOS technology for the THz image sensor application. These power detectors include common-source with and without supply voltage, and common gate with and without supply voltage. The measured responsivities at 332 GHz are 632 kV/W, 13.2 kV/W, 16.2 kV/W, and 9.1 kV/W, respectively. The image resolution of the proposed THz sensor is 2 mm.