• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.502-507
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• 1992

To improve temperature stability, 0.05Pb(SnS11/2TSbS11/2T)OS13T-0.35PbTiOS13T-0.60PbZrOS13T+0.4[wt%]MnO S12T piezoelectic ceramics were manufactured with the addition of CrS12TOS13T by Hot Press method. And the SAW delay line was fabricated and effects of CrS12TOS13T to the propagation characteristics of SAW was investigated, and the SAW filter was fabricated on C4 specimen added by 0.2[wt%] CrS12TOS13T whose propagation characteriatics of surface acoustic wave were the bast and its frequency characteristics was investigated. Electromechancal coupling factor(kS1sTS02T) was 3.11[%] and its temperature coefficient of the center frequency(CS1foT)was -21.27[ppm/$^{\circ}C$] in C4. The 31[MHz]]SAW IF filter of C4 scarcely had diffraction phenomena and therefore it was proper.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.660-666
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• 2015

Surface acoustic wave(SAW) device is used for transporting and patterning micro-scale particles such as cells. In this research, velocity of particles was investigated moved by SAW device with two types of interdigital electrode transducers(IDTs) under various conditions. SAW devices which have single IDTs and double IDTs were designed and fabricated. On the previous studies, resultant velocities of particles were predicted considering output power and power ratio between IDTs-shape. For more accurate prediction, power loss in SAW device and a power difference between two types of IDTs-shape were considered. Maximum error between the test results and predicted values was 5 % so the power loss must be considered in the velocity prediction of the particles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.220-223
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• 2012

Generally, SAW device, which uses Time Domain Sampling, requires high speed AD converter because SAW device (TDS) needs high sampling speed as much as its high data speed. However, the high price of AD converter discourages makers from using it. On the other hand, SAW device, which uses Frequency Domain Sampling, does not required high speed AD converter because SAW device (FDS) does not need high sampling speed. It is very efficient in price comparison to its performance because high processing speed of SAW device (FDS) can be implemented using low price Embedded Systems. The purpose of the thesis is to solve the issues above by designing and realizing SAW device (FDS) using SAW sensor for TDS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.312-315
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• 2012

Generally, SAW device, which uses Time Domain Sampling, requires high speed AD converter because SAW device (TDS) needs high sampling speed as much as its high data speed. However, the high price of AD converter discourages makers from using it. On the other hand, SAW device, which uses Frequency Domain Sampling, does not required high speed AD converter because SAW device (FDS) does not need high sampling speed. It is very efficient in price comparison to its performance because high processing speed of SAW device (FDS) can be implemented using low price Embedded Systems. The purpose of the thesis is to solve the issues above by designing and realizing SAW device (FDS) using SAW sensor for TDS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1730-1736
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• 2013

Slanted and chirp interdigital transducer(IDT) configurations were studied for generating the surface acoustic wave(SAW) with wide bandwidths on a piezoelectric substrate. These devices can be applied to manipulate optical path of light along the waveguide, ultimately used for optical switches and holographic image implementation. Prior to fabrication, the coupling of modes(COM) modeling and simulation were performed to extract optimal design parameters. The optimally designed wideband device showed wide bandwidth of 30MHz, low insertion loss of -25dB, and abrupt side suppression ratio (SSR). Several design conditions were determined during device implementation, such as slanted angle, aperture length, number of fingers, and central frequencies of IDTs. These factors were experimentally analyzed and described in details in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.68-72
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• 1991

In this study, to improve temperature stability 0.05 Pb(Sn$\_$$\frac{1}{2}$/Sb$\_$$\frac{1}{2}$/O$_3$ - 0.35PbTiO$_3$ - 0.60PbZrO$_3$ + 0.4[wt%]MnO$_2$ piezoelctric oeramics of low dielectric constant and large mechanical quality factor were manufactured with the addition of Cr$_2$O$_3$by Hot Press method. And the SAW delay line was fabricated and the propagation characteristics of SAW was investigated, and the SAW filter was fabricated on C4 added by 0.2[wt%] Cr$_2$O$_3$and its frequency characteristics was investigated. The specimen, whose propagation characteristics of surface acoustic wave were the best, was C4 added by 0.2[wt%] Cr$_2$O$_3$, and its electromechanical coupling factor(ks$^2$) was 3.11[%] and its temperature coefficient of the center frequency (C$\_$fo/) was -21.27[ppm/$^{\circ}C$]. The 31[MHz] SAW IF filter of C4 scarcely had diffraction phenomena and its group delay time was 1.4673 ${\pm}$40[ns] in the pass band, and the insertion loss was -24.419[dB] on no impedance matching.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1430-1435
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• 2007

We developed a 440MHz surface acoustic wave (SAW) microsensor integrated with pressure-temperature sensors and ID tag. Two piezoelectric substrates were bonded, in which ${\sim}150\;{\mu}m$ cavity was structured. Four sides were completely sealed by JSR photoresist (PR). Pressure sensor was placed on the top substrate, whereas ill tag and temperature sensor were placed on the bottom substrate. Using network analyzer, the developed microsensor was wirelessly tested. Sharp reflection peaks with high S/N ratio, small signal attenuation, and small spurious peaks were observed. All the reflection peaks were well matched with the coupling of mode (COM) simulation results. With a 10mW RF power from the network analyzer, a ${\sim}1$ meter readout distance was observed. Eight sharp ON reflection peaks were observed for ID tag. Temperature sensor was characterized from $20^{\circ}C$ to $200^{\circ}C$. A large phase shift per unit temperature change was observed. The evaluated sensitivity was ${\sim}10^{\circ}/^{\circ}C$.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.5-8
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• 2000

This paper proposes GaN film as a piezoelectric material for SAW(surface acoustic wave) filters. The fabricated GaN SAW filter exhibited a very high velocity of 5800 ㎧and relatively low insertion loss of -9.9 dB without matching circuit. From Smith's equivalent circuit model, the calculated electromechanical coupling factor (K$^2$) was about 4.$\pm$03％. which is larger than those obtained from other thin film piezoelectric materials and allows the realization of wider filter fractional bandwidths.

• 전기의세계
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• v.31 no.2
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• pp.141-146
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• 1982

In this paper, surface acoustic wave (SAW) bandpass filter is designed using the Fourier series approach and the I$_{0}$-shin window function. And also we studied a method to realize SAW filter using the apodized ID transducer which was fabricated with aluminum metallization of about 1500 A over .deg. thickness on Y-cut Z-propagating LiNbO$_{3}$, crystal by photolithographic technique (lift-off method). Experimental results on SAW bandpass filter responses show good agreements with the theoretical characteristics.s.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.173-176
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• 1999

Frequency responses of the surface acoustic wave(SAW) filters are simulated by using the impulse modeling. The simulation technique of the SAW filters is to use the Fourier transformation to make a correspondence between the impulse response of the filter and the taps in the delay line. Since the Fourier series must be truncated after a finite number of terms, window functions are often used to weight the coefficients to obtain the desirable side-lobe level and bandwidth. The filter design is operated through the iterative simulation procedures. The design process is capable of yielding filters with optimized frequency response characteristics.