• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.111-111
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• 2009

In this work, we discuss simulation of surface acoustic wave device using Comsol Multiphysics. The structure SAW device based on piezoelectric thin film aluminum-nitride (AlN) on silicon was simulated. Some parameters of SAW device such as surface velocity, displacement of piezoelectric thin film were evaluated by software. Many modes and shapes of wave are also discussed in this paper. For evaluation physical parameters of AlN piezoelectric layer, the SAW resonator was modeled and simulation results were also compared with experiment results. we simulated arid evaluated the surface Rayleigh wave of AlN thin film on silicon substrate. Results simulation and experiment showed the surface velocity of AlN thin film was about 5200 m/s and shape of surface wave was also displayed. This paper has also proposed as method to study SAW characteristic of piezoelectric thin film and found out measurement values accurately of film such as stiffness matrix, piezoelectric matrix. These values are very important in calculation and design SAW device or MEMS device based on AlN piezoelectric layer.

• 한국군사과학기술학회지
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• 제12권1호
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• pp.106-113
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• 2009

This paper presents a surface acoustic wave(SAW) micro-electro-mechanical-systems(MEMS) interdigital transducer (IDT) gyroscope with 80MHz central frequency on a $128^{\circ}\;YX\;LiNbO_3$, which is consisted of a two-port SAW resonator, metallic dots and dual delay lines for the sensor and reference oscillators. Reason for using two delay line oscillators is to extract the gyroscope effect by comparing the resonant frequencies between two oscillators and to compensate the temperature effect. Based on the coupling of modes(COM) simulation, an 80MHz two ports SAW resonator and dual delay line were fabricated and characterized by the network analyzer. Obtained sensitivity was $109Hz/deg{\cdot}s^{-1}$ in the angular rate range of $0{\sim}1000deg/s$. Good Linearity and superior directivity were observed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.71-72
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• 2008

In this paper, the effect of thermal annealing on surface acoustic wave (SAW) properties of aluminum nitride (AlN) films were described. The films were fabricated on Si substrates by using Pulsed Reactive Magnetron Sputtering System. The SAW properties of $600^{\circ}C$-annealed AlN films were better than those of both $900^{\circ}C$-annealed AlN films and as-deposited ones. Their SAW velocities (Raleigh mode) and insertion losses were about 5212 m/s and 16.19 dB at $600^{\circ}C$ with the wavelength of $40{\mu}m$. The dependence of characteristics of AlN films on annealing conditions were also evaluated by using Fourier Transform-Infrared Spectroscopy (FT-IR) Spectrums and Atomic Force Microscopy (AFM).

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.83-90
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• 2005

In this paper, we proposed the newly design method for extracting of the saw resonator characteristic. For the parameters of the proposed equivalent model, we adjusted and optimized the variables of several functions. As verification of proposed method, we firstly designed and fabricated cellular saw resonator by using the proposed model resonator. As the simulated and measured results of the proposed design method are almost equaled, we confirmed the usefulness of this method. we knew the usefulness of this method. Finally we designed the 800MHz cellular Tx/Rx band pass filter by using this designed resonator.

• 한국전기전자재료학회논문지
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• 제14권5호
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• pp.435-443
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• 2001

As power durable RF SAW filters, AL-(0∼2wt%)Cu alloy multi-layered thin electrodes were deposited on 42° LiTaO$_3$ piezoelectric substrates by magnetron sputtering process, and then ladder-type RF SAW filters, satisfying the electrical specification of CDMA transmission band, were fabricated through optimizing SAW resonator structures. The temperature of film electrodes in SAW filter was increased with RF power, and reached the maxima to cause a failure of SAW filters at the cut-off frequencies of the RF filter band. As RF power increases, the electrodes of Al-Cu alloy showed higher power durability than that of pure Al. The multi-layer laminated film of Al-1wt.% Cu/Cu/Al-1wt%Cu resulted in the best power durability up to 4W of RF power. Every film electrode, however, was destroyed within seconds whenever applying a critical RF power to SAW filters, regardless of the composition and structure of film electrodes. The breakdown of film electrodes under FR power seems to believe due to the fatigue of electrodes caused by repetitive cyclic stress of surface acoustic wave, which is amplified as RF power increases.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.98-100
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• 1991

A sensitive surface acoustic wave (SAW) sensor for the detection of odorants has been constructed by depositing different phospholipids and fatty acids on the surface of the SAW device wi th the Langmuir-Blodgett technique. The characteristics of SAW device operating at 310 MHz deposited with phosphatidylcholine were analyzed. Amyl acetate, acetoin, menthone and other organic gases showed different affinities. The identification of odorants depending on the species of lipid used for coating is discussed in terms of the similarity of the normalized resonant frequency shift pattern. Using a number of different lipid-coated SAW devices, odorants could be identified by a neural-network pattern recognition with back-propagation algorithm.

• 한국음향학회지
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• 제14권4호
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• pp.64-73
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• 1995

본 연구에서는 카이저 창함수를 이용하여 이동통신용 표면탄성파 필터를 설계하기 위한 CAD를 제작하였다. 제작된 CAD는 아포다이제이션 형태로서 하중함수가 주어진 빗살변환기와 정규형형태의 빗살변환기, 위드드롤로 형태로서 하중함수가 주어진 빗살 변환기 한쌍으로된 변환기와 아포다이제이션 형태로서 하중함수가 주어진 빗살변화기와 정규형 변환기, 반사기를 설치한 공진기 형태의 필터로서 구성되어 있다. 중심 주파수가 222MHz에서 343MHz 영역내의 표면탄성파 필터를 제작된 CAD로 모의 실험 하였다. 본 연구에서 제작된 CAD는 표면탄성파 필터로써 응용될 뿐만 아니라 디지틀 FIR 필터에도 응용될 수 있다.

• 한국통신학회논문지
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• 제38C권9호
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• pp.813-821
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• 2013

본 논문에서는 공진기의 임피던스 변화에 근거한 생체 신호 센서를 제안한다. 제안된 생체 신호 센서는 호흡과 심장 박동 같은 생체 신호를 감지할 수 있고, 시스템은 공진기, 발진기, SAW 필터, 그리고 파워 감지기로 구성되어있다. 인체와 같은 유전체의 주기적인 움직임은 근거리 장 영역 안에서 공진기의 임피던스 변화를 야기하며, 따라서 공진기의 공진 주파수의 변화는 발진기의 발진 주파수 변화에 영향을 끼친다. 여기서 SAW 필터 저지대역의 가파른 주파수 응답특성은 작은 양의 주파수 편차를 큰 변화로 바꿀 수 있다. 기존의 센서의 감지 거리를 확장시키는 것을 목적으로 ISM 대역 870 MHz 대역에서 동작 시켰으며, 최대 거리 120 mm에서 호흡과 심장 박동신호의 검출을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.13-16
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• 2009

In this study, AlN thin films were deposited on a polycrystalline (poly) 3C-SiC buffer layer for surface acoustic wave (SAW) applications using a pulsed reactive magnetron sputtering system. AFM, XRD and FT-IR were used to analyze structural properties and preferred orientation of the AlN/3C-SiC thin film. Suitability of the film in SAW applications was investigated by comparing the SAW characteristics of an interdigital transducer (IDT)/AlN/3C-SiC structure with the IDT/AIN/Si structure at 160 MHz in the temperature range $30-150^{\circ}C$. These experimental results showed that AlN films on the poly 3C-SiC layer were highly (002) oriented. Furthermore, the film showed improved temperature stability for the SAW device, $TCF\;=\;-18\;ppm//^{\circ}C$. The change in resonance frequency according to temperature was nearly linear. The insertion loss decrease was about $0.033dB/^{\circ}C$. However, some defects existed in the film, which caused a slight reduction in SAW velocity.

• Journal of electromagnetic engineering and science
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• 제12권4호
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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.