TY - GEN
T1 - Small (3 × 2.5mm2) surface acoustic wave duplexer for W-CDMA with good temperature and frequency characteristics
AU - Kadota, Michio
AU - Nakao, Takeshi
AU - Nishiyama, Kenji
AU - Kido, Shunsuke
AU - Kato, Masanori
AU - Omote, Ryoichi
AU - Yonekura, Hiroshi
AU - Takada, Norihiko
AU - Kita, Ryoichi
PY - 2007/12/1
Y1 - 2007/12/1
N2 - Small sized surface acoustic wave (SAW) duplexer for wide band code division multiple access (W-CDMA) system with a good temperature coefficient of frequency (TCF) and good frequency characteristics has been required. However, the size of conventional SAW duplexer for W-CDMA using Al-electrode/50- 70°YX-LiNbO3 is large (3.8 × 3.8mm2) and its TCF is not good (-80ppm/°C). So, this duplexer can't satisfy its severe specifications in the all temperature range from -30 to 85°C. When SiO 2 film is deposited on this substrate to improve the TCF, the frequency characteristics is deteriorated by convex portions on the SiO 2 surface caused by SiO2 sputtering. This time, by applying a flip chip bonding process, a flattened-SiO2/Cu-electrode/ substrate structure, and a YX-LiNbO3 substrate, a small sized (3×2.5×1.2mm3) SAW duplexer having good characteristics (such as low insertion loss and large attenuation) and good TCF has been realized for the first time. Here, the SiO2 film is used to improve the TCF, the flattened-SiO2 to obtain high Q, the thick Cu-electrode to obtain the large reflection coefficient, and the YX-LiNbO3 substrate to obtain the large coupling factor and not to generate Rayleigh wave which causes spurious at the SiO2 of 0.3λ and the Cu-electrode of 0.05λ.
AB - Small sized surface acoustic wave (SAW) duplexer for wide band code division multiple access (W-CDMA) system with a good temperature coefficient of frequency (TCF) and good frequency characteristics has been required. However, the size of conventional SAW duplexer for W-CDMA using Al-electrode/50- 70°YX-LiNbO3 is large (3.8 × 3.8mm2) and its TCF is not good (-80ppm/°C). So, this duplexer can't satisfy its severe specifications in the all temperature range from -30 to 85°C. When SiO 2 film is deposited on this substrate to improve the TCF, the frequency characteristics is deteriorated by convex portions on the SiO 2 surface caused by SiO2 sputtering. This time, by applying a flip chip bonding process, a flattened-SiO2/Cu-electrode/ substrate structure, and a YX-LiNbO3 substrate, a small sized (3×2.5×1.2mm3) SAW duplexer having good characteristics (such as low insertion loss and large attenuation) and good TCF has been realized for the first time. Here, the SiO2 film is used to improve the TCF, the flattened-SiO2 to obtain high Q, the thick Cu-electrode to obtain the large reflection coefficient, and the YX-LiNbO3 substrate to obtain the large coupling factor and not to generate Rayleigh wave which causes spurious at the SiO2 of 0.3λ and the Cu-electrode of 0.05λ.
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U2 - 10.1109/ULTSYM.2007.422
DO - 10.1109/ULTSYM.2007.422
M3 - Conference contribution
AN - SCOPUS:48149103367
SN - 1424413834
SN - 9781424413836
T3 - Proceedings - IEEE Ultrasonics Symposium
SP - 1677
EP - 1680
BT - 2007 IEEE Ultrasonics Symposium Proceedings, IUS
T2 - 2007 IEEE Ultrasonics Symposium, IUS
Y2 - 28 October 2007 through 31 October 2007
ER -