• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.367-370
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• 1999

일반적 인 SAW 필터에서 발생하는 선형성의 한계 및 천이대역의 특성을 개선하기 위한 새로운 구조의 이중구조 사다리형 SAW 필터의 최적 설계 방법을 제시하고 그 가능성을 확인하였다. 이중구조 SAW 필터는 일반적인 사다리형 필터의 구조를 바탕으로 하되, 두 개의 서로 다른 필터가 각각 주어진 대역사양을 반반씩 만족시켜 전체의 필터특성이 구현될 수 있도록 하였다. 특히 고주파 대역에서 만족시키기 어려운 정재파비 및 뛰어난 천이대역 특성을 만족시킬 수 있는 장점을 가지며, 이를 위해 withdrawal 가중기법 및 기판상에 encp화된 마이크로 스티 립라인 인덕터를 이용하였다. 우선 이중 구조 필터구조를 결정한 후, microstrip 라인 인덕터의 위치 및 인덕턴스 변화에 따른 필터특성 변화를 살펴보았으며, 필터의 각종 형상변수의 변화에 따른 필터 특성변화를 조사하였다. 이상의 결과를 바탕으로 새로운 방법의 이중구조 SAW 필터의 설계방법을 제시하였으며 그 타당성을 검증하기 위해 1.8 GHz 대역의 RF 필터에 대한 설계 결과를 나타내었다.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.240-245
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• 2007

AlN thin film for SAW filter application was deposited on (100) silicon, sapphire, $Si_{3}N_{4}$/Si, and $Al_{2}O_{3}$/Si substrates by reactive magnetron sputtering method, respectively. The structural characteristics were dependent on the structure of substrates. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Atomic Force Microscope (AFM) have been used to analyze structural properties and preferred orientation of AlN thin films. Preferred orientation and SAW characteristic of AlN were improved by insertion of $Al_{2}O_{3}$ buffer layer. Insertion loss of SAW devices using AlN/Si and AlN/$Al_{2}O_{3}$/Si were about 33.27 dB and 30.20 dB, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.563-567
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• 2004

In this paper, a remote temperature sensor based on surface acoustic wave is introduced and the issues on design, manufacturing, and test of the sensor are addressed. SAW sensors having single and double electrode are prepared on the 128$^{\circ}$ YX-LiNbO$_3$ Substrate. The frequency responses of SAW sensors on the temperature change are compared. To measure the change of center frequency, two center frequencies on the 3dB and 20dB are measured and compared. Since the center frequency on the temperature change from -30$^{\circ}C$ to 80$^{\circ}C$ is linearly changed, the SAW sensor is applicable to the temperature sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.31-35
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• 1996

The cross section of the circular rod type workpiece to be cut in the band saw machine is variable at every moment in the sawing process. When the cutting feed rate is fixed to the constant speed, the cutting edges of the band saw teeth are also variabl eat any moment, so this causes the wear of the land saw teeth and the deterioration of the quality in the surface roughness. In this study, to work out this kind of problem basically, the mean cutting force of a tooth in the band saw was estimated by using the workpiece which was smaller than the interval of each tooth, i.e. band saw pitch, in the thickness. Then the static cutting forces were predicted by appling the mean cutting forces referred above to the mechanistic cutting force model which were analyzed through the geometric profile of a band saw tooth.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.147-155
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• 2000

To reduce the noise from wood cutting saw at the saw mill(lumber mill) or a construction area, some multi-layer sandwich saw blades which a aluminum or copper plate was inserted between the two steel plates were developed and were tested of the wood cutting noise level at various test places. From the research, it was found that the multi-layer saw blade with copper or aluminum plate between steel plates and spot welded 60 points could reduce the wood cutting sound level about 8.3 dB(97.031 dB - 88.743 dB) at indoor test and 3.8 dB(84.805 - 81.638 dB) at field test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.79-83
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• 2014

In this paper, SAW devices are fabricated using various IDT shape(Single/Double) to check an effect of the IDT on SAW device. And based on theory of a particle velocity moved by SAW and IDT, a particle velocity is measured and calculated. Depend on insert power, a particle velocity using Single-IDT SAW device is about two times bigger than Double-IDT SAW device and it's almost same with a theoretical different.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.469-470
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• 2006

Surface Acoustic Wave(SAW) devices can be used to as wireless sensor elements, called SAW transponders, for measuring shysical quantities such as temperature that do not need any power supply and may be accessed wirelessly. SAW devices were fabricated on Y-Z $LiNbO_3$ piezoelectric substrate with a good temperature coefficient property. The signal response of SAW sensor on the temperature change were compared. To measure the change of SAW velocity. Temperature changed form $20^{\circ}C$ to $400^{\circ}C$ was linearly changed, the SAW sensor is application to the temperature sensor.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.5
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• pp.171-174
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• 2016

The diamond wire sawing method to produce silicon wafers for the photovoltaic application is still a new and highly investigated wafering technology. This technology, featured as the higher productivity, lower wear of the wire, and easier recycling of the coolant, is expected to become the mainstream technique for slicing the silicon crystals. However, the saw marks on the wafer surface have to be investigated and improved. This paper discusses the removal of saw marks on diamond wire-sawn single crystalline silicon wafer. With a pretreatment step using tetramethyl ammonium hydroxide ($(CH_3)_4NOH$, TMAH) and conventional texturing process with KOH solution (1 % KOH, 8 % IPA, and DI water), the saw marks on the surface of the diamond wire-sawn silicon wafers can be effectively removed and they are invisible to naked eyes completely.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.90-93
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• 1994

A surface acoustic wave(SAW) sensor for the detection of odorants has been constructed by depositing various phospholipids and fatty acids onto the surface of the SAW device. Applying the Langmuir-Blodgett technique. it was possible to deposit the optimal number of layer which was found to be between 10 and 20. The characteristics of a SAW device operating at 310 MHz deposited with phosphatidyl choline were analysed. Menthone, amylacetate, acetion, and other organic gases sho7\\\\`ed different affinities to the coated lipids. An explanation is given for differant odorant affinities based on the monolayer properties of phospholipids. The identification of odorants depending on the type of lipid used for coating is discussed in terms of a comparison of their normalized resonant frequency chi It pat terns. Using a number of different lipid-coated SAW devices. odorants can be identified by a computerized pattern recognition algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.325-326
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• 2007

SAW filter was designed by optimization technique using impulse sampling. To carry out characteristics of SAW filter the uniform IDT was adapted. And SAW filter was fabricated on $LiNbO_3$ substrates to evaluate frequency response. To apply properties of photolithography, lift off method was used. Lift off method was superior to etch method in fabrication process, frequency response property was measured by network analyzer. From a measurement of acoustic property, SAW propagation velocity was 2663.5m/sec.