• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.597-598
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• 2006

This paper describes a development of a new $1.4{\times}1.1$ and $2.0{\times}1.4mm$ RF SAW filters made by PCB substrate instead of HTCC package, and this technology can reduce the cost of materials down to 40%. We have investigated the multi-layered PCB substrate structures and raw materials to find out the optimal flip-bonding condition between the $LiTaO_3$ wafer and PCB substrates. Also the optimal materials and processing conditions of epoxy laminating film were found out through the experiments which can reduce the bending moment caused by the difference of the thermal expansion between the PCB substrate and laminating film. The new PCB SAW filter shows good electrical and reliability performances with respect to the present SAW filters.

• Journal of the Korea Society for Simulation
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• v.13 no.1
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• pp.25-39
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• 2004

Simulation has been recognized as one of major application areas of world wide web. Over the last several years, most research has been focused on the development of web-based simulation languages mostly using JAVA and validation of simulation modeling on web with the newly developed languages. In this paper, we develop a tentative web-based simulator for a simple unit-load automated warehouse system, named Web-SAW. In constructing Web-SAW, we program a user interface program, a simulation logic program, and an animation program with JAVA while utilizing the class library functions and embodiment environment of existing web-based simulation languages. Web-SAW simulates the automated warehouse system with the user input about system operation, displays the animation on a static background representing the system, and generates the various textual outputs after simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.85-92
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• 2002

In this study, we analyzed and experimented micro-strip line inductors and capacitors for a SAW duplexer, an important devise for mobile communication. For SAW duplexers, micro-strip line lumped elements must have small impedance values, below several tens of nH or several tens of pF, and a small area pattern. In this study, we performed theoretical analysis of flat line type, meander line type, and spiral line type inductors and interdigital capacitors on a LiTaO$_3$ Piezo-crystal. We proposed a measurement method to evaluate small values of lumped elements accurately with network analyzer. In experiments, we confirmed validity of the theoretical analysis method through fabrication and characterization of micro-strip line lumped elements. The analysis method in this paper can be applied to SAW duplexers well as other microwave devices.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.2
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• pp.73-78
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• 2004

AIN thin film has been deposited on the $AI_2$$O_3$substrate with reactive radio frequency( RF) magnetron sputtering method. In this work, elelctromechanical coupling coefficient of AIN thin film was increased with an increase of AIN thin film thickness, and the maximum value was 0.11%. Insertion loss of SAW device was decreased with an increase of AIN thin film thickness and the minimum value was 33［㏈］. SAW velocity of IDTs/AIN/$AI_2$$O_3$structure and IDTs/AIN/$AI_2$$O_3$/Si structure were about 5480［㎧］and 5040［㎧］respectively.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.1-7
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• 1997

SAW filter has been used in mobile communication device, bandpass filter and resonator for merits )f miniaturization and high reliability. Materials for substrate mainly used single crystal such as LiNbO$_{3}$, LiTaO$_{3}$, ZnO. In this study, it was attempted that LiNbO$_{3}$ was substituted for piezoelectric ceramics(PZT4, PZT5A and PZT8) which had simple fabrication process because fabrication of crystal is difficult and it's cost is high. SAW filters were fabricated by the photolithography on piezoelectric ceramics substrates in order to compare their characteristics with LiNbO$_{3}$'s. The experimental value of center frequency was compared with theoretical one. The average difference of center frequency was 3.7%. PZT8 showed the best bandwidth properties among them. It is considered that PZT8 has higher mechanical quality factor and propagation velocity than others.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.11
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• pp.1128-1133
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• 2008

Cellulose based electroactive paper(EAPap) has been developed as a new smart material due to its advantages of piezoelectricity, large displacement, low power consumption, low cost and flexibility. EAPap can be used for a surface acoustic wave (SAW) device using the piezoelectric property of EAPap, resulting in the cost effective and flexible SAW device. In this paper, inter digit transducer(IDT) structure using lift-off technique with a finger gap of 10mm was used for micro fabrication of the cellulose EAPap SAW devices. The performance of IDT patterned SAW device was characterized by a Network Analyzer. The feasibility of cellulose EAPap as a potential acoustic device was presented and explained.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.48-56
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• 2021

Tungsten carbide (WC) circular saws have been widely used to cut plywood. Recently, expensive polycrystalline diamond (PCD) were adopted to extend the tool life of circular saws. This study developed a PCD-WC combination circular saw and compared its performance with that of existing WC and PCD saws. Flank wear of WC saw blades and edge chipping of rectangular PCD was observed during the experiments. The PCD-WC saw replaced half of the chamfered teeth with PCD and applied tough WC for all rectangular teeth. In the experiments, edge chipping was not observed in rectangular WC teeth and the flank wear of chamfered teeth was decreased compared with that of conventional circular saws.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.376-380
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• 2009

Surface acoustic wave (SAW) device is widely used as a bandpass filter, a chemical or physical sensor, and an actuator. In this paper, we propose the capacitive gap measurement system with high precision through the signal processing using SAW device. The research process is mainly composed of theoretical part and experimental part. In theoretical part, equivalent circuit model was used to simulate the SAW response by the change of capacitance. In experimental part, commercialized capacitor was used to see the SAW response by the change of load capacitance. After that, gap adjustment system was made physically and the SAW response by the change of gap which caused the capacitance change was measured. And resolution and stroke was decided comparing the signal change and basic measurement noise level.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.5
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• pp.437-443
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• 2010

SAW device is widely used as band pass filters, chemical or physical sensors, and actuators. In this paper, we propose the capacitive gap measurement system with high precision using SAW device. The research process is mainly composed of theoretical and experimental part. In the theoretical part, equivalent circuit model was used to predict the SAW response by the change of load impedance. In the experimental part, commercialized capacitor was used to see the SAW response by the change of load capacitance to check the feasibility as a sensor unit. After that, experimental setup to measure and adjust the gap was made and the SAW response by the change of gap which caused the capacitance change was measured. Finally, resolution and stroke was decided compared with the signal change and basic measurement noise level.

• Journal of Surface Science and Engineering
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• v.42 no.5
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• pp.216-219
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• 2009

A surface acoustic wave (SAW) filter structure was fabricated employing $4{\mu}m$ thick nanocrystalline diamond (NCD) and $2.2{\mu}m$ thick ZnO films on Si wafer. The NCD film was deposited in an $Ar/CH_4$ gas mixture by microwave plasma chemical vapor deposition method. The ZnO film was formed over the NCD film in an RF magnetron sputter using ZnO target and $Ar/O_2$ gas. On the top of the two layers, copper film was deposited by the RF sputter and inter digital transducer (IDT) electrode pattern (line/space : $1.5/1.5{\mu}m$) was defined by the photolithography including a lift-off etching process. The fabricated SAW filter exhibited the center frequency of 1.66 GHz and the phase velocity of 9,960 m/s, which demonstrated that a giga Hertz SAW filter can be realized by utilizing the nanocrystalline diamond thin film.