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The fabrication of a slanted IDT Transducer for the passband filter  

You Ilhyun (세명대학교 컴퓨터응용과학과)
Kwon Heedoo (I.T.F.(주))
Publication Information
Journal of the Korea Institute of Information and Communication Engineering / v.9, no.2, 2005 , pp. 307-315 More about this Journal
Abstract
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.
Keywords
Single Phase Unidirectional Transducer : SPUDT; Finite Impulse Response : FIR; Slanted Finger Interdigital Transducer : SFIT; Interdigital Transducer : IDT; Weighting;
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