In:
Japanese Journal of Applied Physics, IOP Publishing, Vol. 40, No. 5S ( 2001-05-01), p. 3718-
Abstract:
By composing interdigital transducers (IDTs) and reflectors consisting of films made of a heavy metal such as Au, Ta or W on an ST cut 90°X propagation (direction perpendicular to X-axis) quartz substrate, the authors realized a new type of shear horizontal (SH) wave. This wave has an excellent temperature characteristic, a large electromechanical coupling factor ( k ), and a large reflection coefficient at reflector electrodes. The square of this electromechanical coupling factor ( k 2 =0.28∼0.34%) and the reflection coefficient at reflector electrodes are 2.2∼2.6 times and 30∼35 times, respectively, as large as those of a Rayleigh wave on an ST cut X propagation quartz substrate. The authors applied this technology to filters for the first intermediate frequency (first IF) stage of a global system for mobile communications (GSM) in the nominal center frequency from 200 to 400 MHz. As a result, we succeeded in developing the first IF filter having a low insertion loss, an excellent temperature characteristic (frequency shift: 1 ppm/°C) and a small package size (3×3 mm 2 ), which is as small as a radio frequency (RF) surface acoustic wave (SAW) filter, for the first time.
Type of Medium:
Online Resource
ISSN:
0021-4922
,
1347-4065
DOI:
10.1143/JJAP.40.3718
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2001
detail.hit.zdb_id:
218223-3
detail.hit.zdb_id:
797294-5
detail.hit.zdb_id:
2006801-3
detail.hit.zdb_id:
797295-7
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