• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2374-2381
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• 2007

.We have studied to obtain the properly conditions about impedance matching of the SAW filter for the SPUDT type and the bidirectional transducer type later. And we have studied to obtain the SAW filter for the Slanted Finger Interdigital Transducer(SFIT), was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and then we performed computer-simulated by simulator In case the SPUDT, we have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are $5000{\AA}$ and $3.6{\mu}m$, respectively. And the of the bidirectional transducer, the width of IDT' fingers and the space between IDT' finger and reflector is $1.8{\mu}m$, respectively. Also, we have performed to series connected the SPUDT type with the bidirectional transducer type filter. The frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bahdwidth at the 3dB is probably 5.3MHz after when we have matched impedance. Also, we could obtain that ripple characteristics is less than 0.3dB and insert loss is probably -20dB after when we have matched impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.307-315
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• 2005

We have studied to obtain the SAW filter for the passband was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and then we performed computer-simulated by simulator. We can fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift of the SAW filter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are 5000$\AA$ and 3.6$mu$m, respectively. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 8.2MHz. And we could obtain that return loss is less then 16dB, ripple characteristics is probably 4dB and triple transit echo is less then 18dB after when we have matched impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2662-2670
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• 2009

The effect of the reflector type for the SAW filter on the characteristics of the slanted finger IDT filter have been studied by computer simulation. The IDT was evaporated by Aluminum-Copper alloy. The design condition was optimized by the phase shift of the SAWfilter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness are $5,000{\AA}$, and the width and the space of reflector are $3.6{\mu}m$ and $2.0{\mu}m$, respectively. Frequency response of the fabricated SFIT filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 8.2MHz. And we could obtain that the return loss is less then 16dB, the ripple characteristics is probably 4dB and the triple transit echo is less then 18dB after when we have matched impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.699-706
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• 2010

We have studied to obtain the slanted finger interdigital(SFIT) type filter was formed on the Langasite substrate and was evaporated two IDT electrode by Aluminum-Copper alloy respectively. We can fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift conditions of the SPIT type filter. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflectors are $5000\;{\AA}$ and $3.6{\mu}m$ respectively. At the first sample, we have employed that the distance from the hot electrode to the reflectors is $2.4{\mu}m$ distance from the ground electrode to the reflectors is $1.8{\mu}m$ and the distance from the hot electrode to the ground is $1.5{\mu}m$ respectively. At the other sample, we have also employed that the distance from the hot electrode to the reflectors and the distance from the ground electrode to the reflectors are $2.4{\mu}m$. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 7.3 MHz. And we could obtain that return is less than -20dB, ripple characteristics is probably 3dB and triple transit echo(TTE) is less than -22dB after when we have matched impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.602-608
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• 2005

We have studied to obtain the SAW filter for the Single Phase Unidirectional Transduce. (SPUDT), was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and then we performed computer-simulated by simulator. We can fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulations. Also, we have performed to obtain the properly conditions about impedance matching of the SAW filter for SPUDT. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are 5000A and $3.6{\mu}m$, respectively. And the width of IDT' fingers is $2.4{\mu}m$, and the space between IDT' finger and reflector is $2.0{\mu}m$. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 7.7MHz after when we have matched impedance. Also, we could obtain that ripple characteristics is less than 0.4dB and standing wave ratio is probably 1.5 after when we have matched impedance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1916-1923
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• 2007

We have studied to obtain the SAW filter for the passband was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and thin we performed computer-simulated by simulator. We cm fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift of the SAW filter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are $5000\;{\AA}$ and $3.6{\mu}m$ respectively. And we have employed that the distances from the hot electrode to the reflector are $2.0{\mu}m$, $2.4{\mu}m$ and the distance from the hot electrode to the ground is $1.5{\mu}m$ respectively. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 7,8MHz. And we could obtain that return loss is less then -18dB, ripple characteristics is probably 3dB and triple transit echo is less then -25dB after when we have matched impedance.

• Journal of the Korean Society of Visualization
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• v.20 no.3
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• pp.19-26
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• 2022

In droplet microfluidics, precise droplet manipulation is required in numerous applications. This study presents ultrasonic surface acoustic wave (USAW)-based microfluidic device for label-free droplet separation based on size. The proposed device is composed of a slanted-finger interdigital transducer on a piezoelectric substrate and a polydimethylsiloxane microchannel placed on the substrate. The microchannel is aligned in the cross-type configuration where the USAWs propagate in a perpendicular direction to the flow in the microchannel. When droplets are exposed to an acoustic field, they experience the USAW-induced acoustic radiation force (ARF), whose magnitude varies depending on the droplet size. We modeled the USAW-induced ARF based on ray acoustics and conducted a series of experiments to separate different-sized droplets. We found that the experimental results were in good agreement with the theoretical estimation. We believe that the proposed method will serve as a promising tool for size-based droplet separation in a label-free manner.