• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.347-349
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• 2010

탄성표면파 필터에 관한 여러 가지 모델링이 연구된 이후, 다양한 필터와 공진기가 신호처리용으로 사용되어, 많은 다른 모델들이 이를 분석하고 통합하기위해 유도되어 왔다. 탄성표면파 필터는 크기가 소형이고 제작이 간편하며, 주변의 전자회로와 조합하기 쉬운 장점이 있다. 비대칭의 진폭특성과 비선형 위상특성을 갖는 필터를 설계하고, 설계된 필터의 설계오차를 보정하기 위해서는 임의의 진폭 및 위상특성을 갖는 필터의 설계방법을 연구한다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.393-396
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• 2000

기존의 탄성표면파 듀플렉서 필터는 1/4 파장 정합선로를 이용한 격리회로를 이용하기 때문에 패키지 상에 스트립라인을 구성하는 제작상의 어려움이 있다 본 연구에서는 격리회로가 송신용, 수신용 필터와 함께 온칩상에 위치할 수 있는 새로운 형태의 탄성표면파 필터를 설계하였다. 그 과정으로 송수신 대역을 각각 담당하는 사다리형 필터를 설계하였고, 집중소자 즉, 인덕터와 캐패시터로 구성되는 탄성표면파 듀플렉서 필터의 격리회로를 구성하였으며, 우수한 성능을 가질 수 있도록 각각의 집중소자들의 값을 최적화하였다.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.83-90
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• 2001

Conventional SAW duplexer filters employ a 1/4 wavelength transmission line, which causes difficulty in fabrication of the strip line on the package. Its manufacturing process is also complicated, because it needs integrating process of the separate transmitting filter, receiving filter and isolation circuits. This paper concerns development of a new structure of the duplexer filter that has all the transmitting filter, the receiving filter and the isolation circuit as a one chip device. For composition of the duplexer, we design the component SAW ladder filters and the isolation network consisting of lumped inductor and capacitor elements. Performance of the whole duplexer is optimized by the nonlinear multivariable minimization of a proper target function, and the result is compared with that of commercial filters.

• 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.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.5
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• pp.17-26
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• 1984

This paper reports the design methods and fabrication processes developed for a TV-lF SAW filter. The windowing method, the frequency sampling method, and the time sampling method were studied and compared to obtain a satisfactory initial impulse response. To obtain high attenuation near the trap frequency, diffraction effects were compensated. The 4fo sampling technique was used for avoiding multiple reflections at finger edges and obtaining an asymmetrical frequency response, and effective photolithographic techniques were used for electrode fingers with 11.2$\mu$ width. The developed filter is of sufficiently small size to be cost-effective and satisfies the industry specifications required for mass production.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.481-489
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• 1993

The charge distribution is calculated to analyze the quasi-static impedance of periodic interdigital transducer taking into account the effect of infinite neighboring electrodes. The charge distribution can be represented by the element factor and array factor. The radiation conductance, susceptance and static capacitance of the input and output IDT's with arbitrary voltages are obtained by the charge distribution. The impedance of apodized IDT, is analyzed by multi-track model in which IDT is represented by the parallel connection of the uniform tracks. The calculated input and output impedances are in good agreement with the experimental results.

• The Journal of the Acoustical Society of Korea
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• v.9 no.2
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• pp.53-60
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• 1990

MSK waveforms are advantageous from the point of view of reduced interchannel interference. MSK waveform, however, is more difficult to generate than PSK due to its complex pulse shape. A SAW filter is ideally suited for generation of MSK waveform because it provides accurate control of the required impulse responese and linear phase at high frequncies. In this paper, an implementation of SAW based PSK-MSK convert filter, which can easily convert the high frequency PSK waveform to MSK, is studied.

• The Journal of the Acoustical Society of Korea
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• v.21 no.2
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• pp.102-109
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• 2002

This paper proposes a new design algorithm to optimize the withdrawal weighted SAW ladder devices, Withdrawal weighting on SAW resonators gives enhanced bandwidth and transition band characteristics, so an optimization algorithm was developed for ladder type SAW filters. To illustrate the validity of the technique, this method was applied to the design of RF band CDMA TX SAW filters, and the design results were confirmed to show good agreement with experimental performance.

• The Journal of the Acoustical Society of Korea
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• v.4 no.2
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• pp.48-55
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• 1985

포물선형 혼 도파관을 사용하여 입사파의 음향전력밀도를 증대시킴으로써 압전물질의 압전비선 형성을 이용한 평판형 구조의 탄성 음향파 콘벌버를 제작하고 스펙트럼 확산 통신방식에서 S/N 비가 S 높으며 프로그램이 가능한 자기상관정합 필터로 사용될 수있음을 실험적으로 제시하였다. 본 실험에서 는 포물선형 혼 도파관을 사용한 탄성 음향파 콘벌버를 압전 재료인 YZ-LiNbO\sub 3\ 위에 중심 주파 수 100MHz 압축비 11:1, 적분시간 6인 IDT, 포물선형 혼 도파관 및 출력단자를 설계한 후 이를 포토리 토그라피 바업으로 제작하여 100 MHz 로 펄스 변조된 신호를 탄성 음향파 콘벌버의 양 입력에 인가하 여 자기상관 출력을 얻음으로써 신호 처리 이득이 18dB인 정합필터를 구현하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1767-1775
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• 2003

The SAW device is extensively used as a electro$.$mechanical band­pass filter in which a two­pairs of interdigital transducers are provided over the surface of the piezoelectric substrate. For the design requirement, the central frequency and the bandwidth of the passband, and the attenuation level of the stopband region are specified. The configuration is made so as to satisfy the specification given. The central frequency is mainly determined by the distance between the pair of the finger electrodes. The design is considered as an optimization problem with which the error norm, the distance between the desired characteristics and the calculated for a given model is to be minimized. The delta function model and the electrical equivalent circuit model are utilized to represent the SAW filter characteristics. Genetic algorithm is used for optimization in which apodization of the transducer fingers is chosen as a design variable.