• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.160-165
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• 2005

We have developed SH (shear horizontal) surface acoustic wave (SAW) sensors for detection of the immobilization and hybridization of DNA (deoxyribonucleic acid) on the gold coated delay line of transverse SAW devices. The experiments of DNA immobilization and hybridization were performed with 15-mer oligonucleotides (probe and complementary target DNA). The sensor consists of twin SAW delay line oscillators operating at 100 MHz fabricated on $36^{\circ}$ rotated Y-cut $LiTaO_3$ piezoelectric single crystals. The relative change in the frequency of the two oscillators was monitored to detect the hybridization between target DNA and immobilized probe DNA in pH 7.4 PBS (phosphate buffered saline) solution. The measurement results showed a good response of the sensor to the mass loading effects of the DNA immobilization and hybridization with the sensitivity up to $1.55{\cal}ng/{\cal}ml/Hz$.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.657-662
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• 2003

Optimum Hamming apodized acousto-optic 2${\times}$2 add/drop multiplexers, using SiO$_2$ film loaded acoustic waveguide with angular offset to the Ti:LiNbO$_3$ waveguide, were fabricated. The four-port device consists of two input waveguides, a polarization beam splitter (PBS), two polarization conversion/acoustooptic tuning waveguide sections, a second PBS and two output waveguides. Insertion loss <7.1 ㏈ has been obtained and side-lobe of -19 ㏈ for -32 ㎽ RF driving power has been realized. Add/drop performance has been confirmed and a linear tuning rate of 8.1 nm/MHz and a 3 ㏈ spectral width of -1.5 nm were demonstrated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.235-235
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• 2009

This paper describes the influence of a polycrystalline (poly) 3C-SiC buffer layer on the surface acoustic wave (SAW) properties of poly aluminum nitride (AlN) thin films by comparing the center frequency, insertion loss, the electromechanical coupling coefficient ($k^2$), andthetemperaturecoefficientoffrequency(TCF) of an IDT/AlN/3C-SiC structure with those of an IDT/AlN/Si structure, The poly-AlN thin films with an (0002)-preferred orientation were deposited on a silicon (Si) substrate using a pulsed reactive magnetron sputtering system. Results show that the insertion loss (21.92 dB) and TCF (-18 ppm/$^{\circ}C$) of the IDT/AlN/3C-SiC structure were improved by a closely matched coefficient of thermal expansion (CTE) and small lattice mismatch (1 %) between the AlN and 3C-SiC. However, a drawback is that the $k^2(0.79%)$ and SAW velocity(5020m/s) of the AlN/3C-SiC SAW device were reduced by appearing in some non-(0002)AlN planes such as the (10 $\bar{1}$ 2) and (10 $\bar{1}$ 3) AlN planes in the AlN/SiC film. Although disadvantages were shown to exist, the use of the AlN/3C-SiC structure for SAW applications at high temperatures is possible. The characteristics of the AlN thin films were also evaluated using FT-IR spectra, XRD, and AFM images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.8-13
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• 2006

Recent RF SAW filters are made using a HTCC package with a CSP(chip scale Package) technology. This paper describes a development of a new $1.4{\times}1.1\;and\;2.0{\times}1.4mm$ RF SAW liters 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.343-345
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• 2015

Currently, SAW Device has been used as a frequency filter using the property of passing only a desired frequency with a narrow bandwidth. However, the areas of activity in various fields since the permanent advantages can be widened by using a non-powered. These sensor tags using SAW Device has been done, but a lot of research, the development of the state still insufficient for Reader Platform. How to read the value of the ID Tag Using SAW Device has a time domain sampling (TDS) method and a frequency domain sampling (FDS) method. The purpose of the paper, we use the FDS method that requires high-speed processing with a relatively slow sampling rate does not require high-speed sampling. Reader Platform was the way to detect ID through PC as FDS way, but It is based on the Cortex-A9 processor and it works a low price, compact and real-time Reader Platform.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.227-233
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• 2012

This paper describes a novel and compact biosensing platform using an RF active system. The proposed sensing system is based on the oscillation frequency deviation due to the biomolecular binding mechanism on a resonator. The impedance variation of the resonator, which is caused by a specific biomolecular interaction results in a corresponding change in the oscillation frequency of the oscillator so that this change is used for the discrimination of the biomolecular binding, along with concentration variation. Also, a Surface Acoustic Wave (SAW) filter is utilized in order to enhance the biosensing performance of our system. Because the oscillator operates at the skirt frequency range of the SAW filter, a small amount of oscillation frequency deviation is transformed into a large variation in the output amplitude. Next, a power detector is used to detect the amplitude variation and convert it to DC voltage. It was also found that the frequency response of the biosensing system changes linearly with three streptavidin concentrations. Therefore, we expect that the proposed RF biosensing system can be applied to bio/medical applications capable of detecting a nano-sized biomolecular interaction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.196-200
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• 2009

Lithium niobate ($LN:LiNbO_3$) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in surface acoustic wave (SAW). To manufacture LN devices, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult b traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters such as down force and relative velocity, were investigated for the LN CMP process To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance.

• Electrical & Electronic Materials
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• v.6 no.2
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• pp.109-114
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• 1993

본 논문에서는 0.05Pb(Sn$_{1}$2/Sb$_{1}$2/)-0.35PbTiO$_{3}$-0.60PbZrO $_{3}$+0.4[wt%] MnO$_{2}$ 조성을 갖는 3성분계 압전세라믹스에 Cr$_{2}$O$_{3}$ 의 첨가량을 변화시켜서 지연선을 제작하고 탄성표면파를 여기시켜 전파속도를 측정하였으며 EMMAS 기준에 따라 각 시편의 재료정수를 측정하고 이를 압전방정식에 적용하여 매질에 따라 여기되는 탄성표면파의 계산속도를 이론적으로 산출한 후 이를 지연선에서 측정된 실험속도와 비교하여 재료의 특성이 탄성표면파의 전파특성에 미치는 영향을 조사하였다. 그 결과 SAW 지연선에서 측정된 탄성표면파는 Generalized Rayleigh Wave였으며 재료의 특성이 우수한 시편일 수록 계산속도와 측정속도와의 차가 적었던 것으로 나타났고 오차한도는 평균 99.39[%]였으므로 실험속도 측정방법이 feed through 현상없이 우수한 측정방법이었음을 알 수 있었다.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.783-791
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• 1994

Piezoelectric ZnO thin films were deposited on 7059 glass substrate by rf magnetron sputtering. The effects of deposition parameter, such as rf power, gas pressure and $O_{2}$/Ar gas ratio, on the crystallinity and electrical properties of the deposited ZnO thin films were studied. It was found that the deposition rate was higher than the previously reported values. ZnO films were suitable for SAW filter since a standard deviation of XRD (002) peak rocking curve was less than $6^{\circ}$. ZnO thin films, which were deposited at $O_{2}$/Ar ratio larger than 25%, showed high resistance. SAW filter was fabricated using ZnO film, of which thickness was 0.25 of the wavelength of the propatating surface acoustic wave. The measured frequency response was consistent with the calculated one. The SAW filter had center frequency 39.08 MHz, phase velocity 2501 m/sec and insertion loss 29 dB.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.56-56
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• 2003

최근 정보통신 분야의 급격한 발달로 인하여 무선통신에 사용되는 주파수 영역 또한 계속 높아짐에 따라 대역통과 필터 소자의 삽입 손실, 소비 전력, 크기, MMIC화에 대한 많은 연구가 진행되고 있다 압전 현상을 이용한 박막형 공진기가 이러한 요구를 충족시키고, 현재의 SAW filter를 대체할 소자로 떠오르고 있다. 본 실험에서는 단결정 미세 구조를 만들 수 있고, 압전 효과 또한 우수하며, Surface Micromachining보다 비교적 제조 공정이 간단하고 선택적 에칭이 가능한 Bulk Micromachining을 이용하여 Si$_3$N$_4$ Membrane을 이용한 중심주파수 5.2GHz인 두께 진동모드 Film Bulk Acoustic Wave Resonator(FBAR)를 제작하고 공진기의 고주파 특성을 평가하였다. Membrane구조 형성을 위해 Backside면인 Si$_3$N$_4$, Si은 RIE(Reactive Ion Etching)와 선택적 에칭용액인 KOH로 각각 에칭하여 Membrane을 갖는 구조로 중심주파수 5.2GHz인 두께 진동모드 FBAR를 설계 및 제조하였다. 체적 탄성파 공진 현상은 r.f Magnetron Sputtering법으로 증착한 AIN 압전박막과 Mo전극으로부터 발생 가능하였다. 본 연구에서는 0.9$\mu\textrm{m}$-Si$_3$N$_4$ Membrane을 이용해 FBAR를 제작/평가하고, RIE을 통해 Membrane을 제거해 가면서 공진기의 특성 즉, Quality factor와 유효전기기계결합계수(K$_{eff}$) 및 S parameter특성을 비교 측정해 보았다. 측정해본 결과 Membrane Free일때가 훨씬더 공진 특성이 우수함을 볼 수 있다