Browsing by Author "Cheng, Yu-Ting"

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A 13.56 MHZ METAMATERIAL FOR THE WIRELESS POWER TRANSMISSION ENHANCEMENT IN IMPLANTABLE BIOMEDICAL DEVICES
(2019-01-01)
Chen, Kuan-Jung
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Chen, Wei-Ming
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Tan, Li-Yang
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Cheng, Yu-Ting
;
Ker, Ming-Dou
This paper presents a 13.56MHz metamaterial for wireless power transmission (WPT) enhancement in implantable biomedical devices based on the evanescent wave coupling mechanism. The power transmission efficiency (PTE) will increase from 46 to 51% with the metamaterial while the transmitting and receiving antennas are placed with a 1 cm distance and lcm offset horizontal misalignment, will increase from 39 to 46% with the metamaterial while the two antenna planes are placed at a distance of 1.5 cm with an axial offset of 15, and will increase from 28 to 50% with two pieces of metamaterial placed with a 0.5cm distance while the two antenna planes are placed with a 1.5 cm distance and 1 cm offset horizontal misalignment.
A Broadband Interconnect for THz Heterogeneous System Integration
(2013)
Li, Chun-Hsing
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Wu, Jan-Jr
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Kuo, Chien-Nan
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Cheng, Yu-Ting
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Kuo, Ming-Ching
A broadband interconnect for THz heterogeneous system integration is proposed using a resonator coupling technique. Two resonators, deployed on a chip and a carrier, respectively, are coupled through the electromagnetic field to provide a low-loss interconnect in a broadband manner. Simulation results indicate an insertion loss of 0.32 dB at 170 GHz while covering 3-dB bandwidth from 100 to 344 GHz. Measurement can be conducted to verify its performance only from 140 GHz to 220 GHz, due to equipment limit. The measured minimum insertion loss is 0.47 dB at 164 GHz.
A capacitive micromachined ultrasonic transducer array for minimally invasive medical diagnosis
(2008-06-01)
Chen, Jingkuang
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Cheng, Xiaoyang
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Chen, Chien-Chang
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Li, Pai-Chi
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Liu, Jian-Hung
A capacitive micromachined ultrasonic transducer (CMUT) array for minimally invasive medical diagnosis has been developed. Unlike traditional ultrasonic transducers, which generally use a bulky piece of substrate, this transducer array was integrated on a 40-mu m-thick micromachined silicon substrate into a probe shape with a typical shank width of 50-80 mu m and a shank length of 4-8 mm. For 1-D arrays, 24-96 CMUT devices were integrated on one such silicon probe and formed an accurately configured phase array. In addition to miniaturization, reduction of the substrate thickness also decreases the intertransducer crosstalk due to substrate Lamb waves. Due to its miniature size, this array can be placed or implanted close to the target tissue/organ and can perform high-resolution high-precision diagnosis and stimulation using high-frequency ultrasounds. The issue of conflict between resolution and penetration depth of ultrasonic diagnosis can therefore be resolved. A two-layer polysilicon surface micromachining process was used to fabricate this device. Suspended polysilicon membranes of diameters ranging from 20 to 90 mu ms and thicknesses from 1.0 to 2.5 mu m were used to generate and detect ultrasounds of frequencies ranging from I to 10 MHz. B-mode imaging using this transducer array has been demonstrated.
A Combined Process of Liftoff and Printing for the Fabrication of Scalable Inkjet Printed Microstructures on a Flexible Substrate
(2015-04-01)
Fu, Yu-Min
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Liang, Yen R.
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Cheng, Yu-Ting
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Wu, Pu-Wei
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材料科學與工程學系
In this paper, a combined process of liftoff and printing (CPLoP) techniques is introduced to realize size-scalable printed silver microstructures with line widths ranging from 5 to 70 mu m and resistivities of similar to 9.8 mu Omega . cm on a flexible polyimide substrate via thermal sintering at 300 degrees C for 30 min. In addition, a printed interdigitated capacitor with an electrode line width and spacing of 10 mu m and a printed spiral square inductor with a 10-mu m line width and 5-mu m spacing in an area of 1 mm(2) have been successfully demonstrated with an area capacitance and inductance of 0.43 pF/mm(2) at 10 KHz and 1.054 mu H/mm(2) up to 100 KHz, respectively, which are the orders of magnitude performance improvement in comparison with the contemporary inkjet-printed capacitors and inductors. Owing to the significant reduction of energy demand in processing tools and waste generation in processing materials, the results have revealed that the CPLoP process can facilitate the advancement of printing manufacture technology for microelectronics applications.
A COMBINED PROCESS OF SILICON SHADOW MASKING AND INKJET PRINTING (SSMP) FOR MAKING GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE MICROSTRUCTURES FOR SELECTIVE CELL CULTURING APPLICATIONS
(2019-01-01)
Kang, Che-Hao
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Fu, Yu-Min
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Kao, Chin-Chuan
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Yang, Jia-Wei
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Tseng, Ming-Liang
This paper demonstrates a combined process of silicon shadow masking and inkjet printing (SSMP) to fabricate graphene oxide (GO) and reduced graphene oxide (rGO) line features with a width ranging from 20 to 70 mu m on varieties of substrates, such as PDMS, SiO2 , Kapton, etc. for selectively cell (RPE and PC-12 cells) culturing applications. The rGO with an electrical resistance of 33.48k Omega/ is characterized via a printed four point resistivity measurement structure. Owing to the characteristics of low chemical usage, low process temperature and complexity, and high fault tolerance of inkjet printers, the process technique has shown its potential for biomedical applications in terms of flexible cell culturing platform fabrication.
A comparison of individual and group polling strategies on students\' academic performance and attention level
(2015)
Sun, Jerry Chih-Yuan
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Chen, Ariel Yu-Zhen
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Yeh, Katherine Pin-Chen
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Cheng, Yu-Ting
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Lin, Yu-Yan
The purpose of the study was to investigate the effect of polling technologies integrating with strategies on students\' academic performance and related brainwave signals. The participants were 34 students who registered in the educational research methodology course in a national university in Taiwan. The pre-class quiz, in-class quiz, brainwave of attention levels, open-ended questionnaires, and the 20-minute structured interview were used in this study. This study was conducted over a period of three weeks. Over the three weeks, the teacher conducted "three types of polling activities." Week 1 was devoted to individual clicker polling, Week 2 to group polling on tablets, and Week 3 to group polling on tablets with a competition game. The results showed that polling systems help promote learning outcomes, and if a team was given an opportunity to discuss a topic after it was announced, this would help to increase attention levels. This study suggests that future researchers could design team polling activities in which students can take turns acting as a group leader in order to help build a team consensus and to avoid passive group member participation.
A Continuous-Wave THz Imaging System
(2013)
Pei, Ting-Hang
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Huang, Yang-Tung
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Wang, Yu-Jiu
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Chen, Wei-Zen
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Kuo, Chien-Nan
We develop a continuous wave terehertz (THz) imaging system operating at 288 GHz. This imaging system simply consitutes three parts including the source, two optical lenses, and the detector. The entire size is smaller than the tranditional pulsed THz imaging system. In this developed system, the THz wave is generated by a horn attenna which concentrates the wave in an azimuth angle of 3 degrees similar to 5 degrees. The source originates from a singnal generator, and then the frequency increases to 288 GHz after passing through an 8X multiplier. Next, THz wave is focused by a THz lens on the test sample. By controling the sample position in the x-z plane, we can scan it pixel-by-pixel in which each step along the x- or z- axes is 0.1 mm. After penetrating the test sample, another lens collects the transmitted THz wave and focuses them into the thermal detector. This detector can disply the collected THz power. Finally, by drawing the detected power of each pixel, a transmitted-intensity figure for all pixels is obtained. The resolution of this THz imaging system is about 1 similar to 2 mm at present. We have measured human molar tooth and obtained its transmitted figures. Besides, we also develop a technology to adjust the positions of the source and detector by a system containing one laser, one beamsplitter, and two mirrors. The relative positions between the source and detector is very important. The input of the source and the output of the detector are small so that they have to aim at each other very accurately in order to collect maximum transmitted power in the detector.
A Flexible Inductive Coil Tag for Household Two-Wire Current Sensing Applications
(2012-06-01)
Chen, Yung-Chang
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Yu, Sung-Chu
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Cheng, Shih-Hsien
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Cheng, Yu-Ting
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電子工程學系及電子研究所
This paper presents a flexible inductive coil tag for sensing the electric current in the two-wire power cords of household goods. The tag is fabricated using a complementary metal-oxide semiconductor compatible SU-8 flexible technology which provides unique device characteristics of low-cost, reliability and pervasiveness. With a 30-turns coil design in an area of 0.5x1 cm(2), the coil tag can provide sensitivity of 18 and 21 mu V/A for detecting 50-and 60-Hz electric current in the ampere regime, respectively.
A Flexible Inductive Coil Tag for Household Two-Wire Current Sensing Applications
(2012-06-01)
Chen, Yung-Chang
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Yu, Sung-Chu
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Cheng, Shih-Hsien
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Cheng, Yu-Ting
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電子工程學系及電子研究所
This paper presents a flexible inductive coil tag for sensing the electric current in the two-wire power cords of household goods. The tag is fabricated using a complementary metal-oxide semiconductor compatible SU-8 flexible technology which provides unique device characteristics of low-cost, reliability and pervasiveness. With a 30-turns coil design in an area of 0.5 x 1 cm(2), the coil tag can provide sensitivity of 18 and 21 mu V/A for detecting 50- and 60-Hz electric current in the ampere regime, respectively.
A FlexibleWO(3)-Based pH Sensor Array for 2-D pH Monitoring Using CPLoP Technique
(2018-06-01)
Fu, Yu-Min
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Pan, Jia-Chyi
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Tsou, Kun-Lin
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Cheng, Yu-Ting
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電子工程學系及電子研究所
In this letter, we demonstrate an inkjet-printed WO3-based pH sensor array using WO3/Ag and Ag/AgCl as working and reference electrodes, respectively, on a flexible polyimide substrate. Pre-treated by Tollen's reagent, the printed Ag lines as sensor interconnects can exhibit a denser microstructure with lower electrical resistivity. As a result, the WO3 nanoparticles can be well printed and sintered at 120 degrees C on the Ag lines as the working electrodes of the pH sensors. Experimental results show the sensitivity of the pH sensor to be as high as -24.4 mV/pH. The array comprising six pH sensors shows potential for real-time 2-D pH sensing applications.
A LOW TEMPERATURE INKJET PRINTING AND FILLING PROCESS FOR LOW RESISTIVE SILVER TSV FABRICATION IN A SU-8 SUBSTRATE
(2017-01-01)
Yang, Tsung-Han
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Guo, Zi-Li
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Fu, Yu-Min
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Cheng, Yu-Ting
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Song, Yen-Fang
The paper presents a low temperature (with 60 degrees C) inkjet printing and filling process to realize low resistive Ag TSV (Through Substrate Vias) with the aspect ratio of via depth vs. diameter from 2 to 5 in a SU-8 substrate potential for flexible microsystem packaging applications. Combining humidity control and layer-by-layer Ag mirror reaction, the proposed process technology can accomplish a fully filled TSV with the lowest electrical resistivity of similar to 450 mu Omega.cm in comparison with the prior printing and filling technologies.
A Method For Predicting Inductance And Self-Resonant Frequency Of A Spiral Inductor
(2007-09-13)
Chen, Chien-Chang
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Cheng, Yu-Ting
In this invention, a closed-form integral model for on-chip freely suspended rectangular spiral inductor is presented. The model of this invention bases on the Kramers-Kronig relations, field theory, and solid state physics to characterize a spiral inductor which RFIC designers could easily have the optimal design utilizing this analytical method. Meanwhile, this model can provide satisfactory prediction to the inductance and self-resonant frequency of the spiral inductor without complicated geometry analysis. Furthermore, unlike conventional formulations only based on circuit parameters, this model could safely predict the inductance and the self-resonant frequency when altering the material (excluding ferromagnetic materials) of a spiral inductor.
A Microfabricated Coil for Implantable Applications of Magnetic Spinal Cord Stimulation
(2015)
Fu, Yu-Min
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Chen, Che-Yu
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Qian, Xin-Hong
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Cheng, Yu-Ting
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Wu, Chung-Yu
In this paper, a microfabricated inductive coil comprising of 125-turn coil windings and a MnZn-based magnetic core in a volume of 200 mm(3) is presented for the magnetic neural stimulation in a spinal cord. The coil winding with the parallel-linkage design instead of the typical serial-linkage one is proposed not only to provide better design flexibility to the current mode driving circuit but also to simplify the fabrication process of the 3-D inductive coil, which can further advance the coil miniaturization. Experimental results show the microcoil with a 1.5 A, 1 kHz square-wave current input can induce a voltages of 220 mu V on the conducting wire with an impedance of similar to 0.2 Omega @ kHz, 1 mm separation.
A Polar Modulated Tri-band Power Amplifier Using Flexible Substrate Based MEMS Switches
(2010-01-01)
Lai, Chung-Min
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Chao, Tzu-Yuan
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Tsou, Wen-An
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Chou, Mei-Fen
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Cheng, Yu-Ting
In this work, the phase compensation techniques by means of self-biasing control and an additional tuning capacitor for polar modulated tri-band Class-E power amplifier is proposed. The tri-band power amplifier operating at 2.3 similar to 2.7/3.3 similar to 3.8/5.1 similar to 5.8 GHz for WLAN and WiMAX applications adjusts low loss Micro-Electro-Mechanical-Systems (MEMS) switches to select the matching networks. The improvement of phase distortion and system relative constellation error (RCE) is 36.4 degrees and 8.9dB, respectively. Simulation results shows that the maximum power-added efficiency (PAE) of 34.9%, drain efficiency of 37.3%, and output power of 18.8dBm from 2.8V supply can be achieved in 0.18 mu m CMOS Technology.
A wafer-level hermetic encapsulation for MEMS manufacture application
(2006-08-01)
Liang, Zhi-Hao
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Cheng, Yu-Ting
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Hsu, Wensyang
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Lee, Yuh-Wen
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機械工程學系
In order to simplify the processing complexity and cut down the manufacturing cost, a new wafer bonding technique using ultraviolet (UV) curable adhesive is introduced here for microelectromechanical systems (MEMS) device packaging and manufacturing applications. UV curable adhesive is cured through UV light exposure without any heating process that is suitable for the packaging of temperature-sensitive materials or devices. A Pyrex 7740 glass is chemically wet etched to form microcavities and utilized as the protection cap substrate. After a UV-curable adhesive is spin-coated onto the glass substrate, the substrate is then aligned and bonded through UV light exposure with a device substrate below. Electrical contact pad opening and die separation are done simultaneously by dicing. Two different testing devices, a dew point sensor and capacitive accelerometer, are built to evaluate the package strength and hermeticity. After the dicing process, no structural damage or stiction phenomenon is found in the packaged parallel capacitor. The acceleration test results also indicate that the package using the Loctite 3491 UV adhesive with 150 mu m bond width can survive more than 300 days at a 25 degrees C and 100% relative humidity working environment.
AN ALIGNMENT SCHEME FOR LOW COST AND HIGH PRECISION SLOB FABRICATION USING AN ELECTROMAGNETIC MICROACTUATOR WITH 5 DOF
(2019-01-01)
Chen, Chih-Chung
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Fu, Yu-Min
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Hsu, Hsin-Feng
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Cheng, Yu-Ting
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電子工程學系及電子研究所
This paper presents an alignment scheme for SiOB fabrication using an electromagnetic force-driven microactuator with five degrees of freedom (5 DOF) of movement. The actuator comprising four sets of corrugated springs and spiral coils driven by Lorentz and reluctant force respectively can accomplish linearly horizontal and vertical displacement and tilt angle ranging within 2 and 10.5Am, and 0.1 degrees for positioning optical lens with a resolution of 0.mu m, which has been experimentally validated to facilitate h scheme feasibly.
AN IMPLANTABLE ULIRASONIC DOPPLER BLOOD FLOWMETER
(2006)
Cheng, Xiaoyang
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Chen, Jingkuang
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Zhang, Tongsheng
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Chen, Chien-Chang
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Cheng, Yu-Ting
A miniature ultrasonic transducer array for minimally invasive blood flow measurement has been developed. Compare with laser Doppler flowmeter, this tool is much smaller in size and is capable of reaching deep inside the tissue to monitor blood flow not accessible by the laser beam. Compared with traditional ultrasound Doppler flowmeter, this miniature tool is able to achieve more accurate measurement by using high frequency ultrasounds. The silicon substrate of the transducers array was micromachined into a probe shape using double-sided dry etching. The typical cross-sectional dimension of the silicon probe is 40 mu mx80 mu m. Arrays comprising 24-32 transducers were prototyped and tested. The 46 mu m-diameter drum shaped ultrasound transducers operate at a voltage lower than 40 volts, generate and receive ultrasound at a central frequency of 5.8MHz, and has a bandwidth of about 80%. A new polysilicon surface micromachining process was developed for fabrication of the transducer. The new process separates all the conductors from the silicon nitride film and reduces the charging problem associated with nitride-conductor interface.
AN INKJET PRINTED PIEZORESISTIVE BACK-TO-BACK GRAPHENE TACTILE SENSOR FOR ENDOSURGICAL PALPATION APPLICATIONS
(2017-01-01)
Fu, Yu-Min
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Chou, Meng-Chuin
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Cheng, Yu-Ting
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Secor, Ethan B.
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Hersam, Mark C.
The paper presents a tactile sensor design mimicking human finger touch to differentiate tissue hardness for endosurgical palpation applications. The sensor comprises two inkjet-printed piezoresistive graphene-based sensing elements linked back-to-back for force and displacement detection, respectively. Experimental results indicate the sensor registers 2.1 and 5.3 mN force feedback from the fat and muscle tissues of pig, respectively, when pressed to the tissues with the same 100 mu m displacement. This difference of similar to 2.5 times in force feedback provides a compelling method by which doctors can more intuitively perceive hardness and tissue differences during endosurgery in comparison with the prior arts.
An Inkjet Printing Technique for Scalable Microfabrication of Graphene-Based Sensor Components
(2020-01-01)
Fu, Yu-Min
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Chou, Meng-Chuin
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Kang, Che-Hao
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Cheng, Yu-Ting
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Wu, Pu-Wei
This paper presents a versatile and precise graphene patterning technique using the combined process of masking and inkjet printing. A graphene-based structure is fabricated by first defining the structural pattern and position using a masking mold, which can be either electroplated copper or deep reactive ion etching (DRIE) silicon shadow mask, followed by inkjet deposition of graphene ink and lift-off. The hybrid technique can realize high-fidelity, high-resolution graphene-based microstructures including free-standing and cantilever beams, four-point resistive measurement structures, and piezoresistive sensing elements with a minimum line width of similar to 20 mu m. Moreover, this method can facilitate the micropatterning of graphene oxide (GO) and reduced graphene oxide (rGO) on substrates such as polydimethylsiloxane (PDMS) and SiO2/Si for selective cell culturing applications. Owing to the characteristics of low chemical usage, low process temperature and complexity, and high fiexibility and fault tolerance of inkjet printing, this technique demonstrates compelling potential for a variety of biomedical applications.
An Inkjet-Printed Flexible Non-Enzymatic Lactate Sensor for Clinical Blood Plasma Test
(2020-04-01)
Huang, Yi-Syuan
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Chen, Kuan-Yu
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Cheng, Yu-Ting
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Lee, Chih-Kuo
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Tsai, Hsiao-En
In this letter, we demonstrate a fully inkjet-printed electrochemical lactate sensor. The sensor is inkjet-printed on a flexible substrate, Kapton film, where silver nanoparticles (Ag NPs) are printed as conductive electrodes. The working and reference electrodes of the sensor are Ag NPs/NiO NPs/Polyurethane (PU) and Ag/AgCl(s)/PU layers respectively. The inkjet-printed PU film can not only prevent the annihilation of the Ag NPs resulting from the dissolution of Ag and the formation of AgCl in the phosphate-buffered saline (PBS) but also stabilize the lactic acid measurements by maintaining a potential variant within 2% at different lactate concentrations. The as-printed sensor exhibits a linear sensitivity of 8.86nA/mM/mm(2) (R=99.6%) in the range from 0.6 to 2.2 mM. Clinical blood plasma testing results show that the trends of lactic acid change in patients measured by the sensor are the same as the ones measured using the existing detection method, colorimetric assays, in a tertiary university-affiliated hospital.