| 摘要 |
PROBLEM TO BE SOLVED: To provide a longitudinally coupled resonator surface acoustic wave (SAW) device having a balance/unbalance (balun) input/output function and having an improved balance between balance terminals. SOLUTION: Longitudinally coupled SAW filters 8, 14, 17a and 18 are respectively provided on a piezoelectric substrate 30 so as to have the balun input/ output function. An electrode finger positioned at the outermost region of an IDT (interdigital transducer) 23a having the phase which is inverted 180°from the other IDTs to obtain the balun input/output function is thinned, and a dummy electrode finger 23b connected to the ground is provided at the thinned position. COPYRIGHT: (C)2003,JPO
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