TY - JOUR
T1 - Surface acoustic wave duplexer composed of SiO2/Cu electrode/LiNbO3 structure having convex and concave portions
AU - Nakai, Yasuharu
AU - Nakao, Takeshi
AU - Nishiyama, Kenji
AU - Kadota, Michio
PY - 2009/7/1
Y1 - 2009/7/1
N2 - The transition bandwidth of 20MHz between the transmission (Tx: 1850-1910MHz) and the receiving (Rx: 1930-1990MHz) bands of personal communication service (PCS) handy phones in the United States (US) is very narrow compared with those of other systems. We have already realized surface acoustic wave (SAW) duplexers with sizes of 5.0 × 5.0 × 1.7 and 3.0 × 2.5 × 1.2 mm3 for PCS handy phones in the US with an excellent temperature coefficient of frequency (TCF) by using a shear horizontal (SH) wave on a flattened SiO2/Cu electrode/36-48° YX-LiTaO 3 structure and a Rayleigh wave on a SiO2/Cu electrode/120-128° YX-LiNbO3 structure. Although the surface of the above-mentioned structures is flattened SiO2, we have also studied the shape of the SiO2 surface. As a result, in addition to increasing the stop-band width, which corresponds to the reflection coefficient, the TCF and power durability have been improved by forming convex portions on the surface of the SiO2 over the interdigital transducer (IDT) gaps.
AB - The transition bandwidth of 20MHz between the transmission (Tx: 1850-1910MHz) and the receiving (Rx: 1930-1990MHz) bands of personal communication service (PCS) handy phones in the United States (US) is very narrow compared with those of other systems. We have already realized surface acoustic wave (SAW) duplexers with sizes of 5.0 × 5.0 × 1.7 and 3.0 × 2.5 × 1.2 mm3 for PCS handy phones in the US with an excellent temperature coefficient of frequency (TCF) by using a shear horizontal (SH) wave on a flattened SiO2/Cu electrode/36-48° YX-LiTaO 3 structure and a Rayleigh wave on a SiO2/Cu electrode/120-128° YX-LiNbO3 structure. Although the surface of the above-mentioned structures is flattened SiO2, we have also studied the shape of the SiO2 surface. As a result, in addition to increasing the stop-band width, which corresponds to the reflection coefficient, the TCF and power durability have been improved by forming convex portions on the surface of the SiO2 over the interdigital transducer (IDT) gaps.
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U2 - 10.1143/JJAP.48.07GG02
DO - 10.1143/JJAP.48.07GG02
M3 - Article
AN - SCOPUS:72049083221
VL - 48
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 7 PART 2
M1 - 07GG02
ER -