| 摘要 |
A vertically coupled resonator-type elastic surface wave filter equipped with: an unbalanced terminal (10); balanced terminals (20); a piezoelectric substrate; a first elastic surface wave filter part (11); a second elastic surface wave filter part (12); an unbalanced signal line; balanced signal lines; a pair of inter-stage wires connecting the first elastic surface wave filter part (11) and the second elastic surface wave filter part (12); and ground wires. The first elastic surface wave filter part (11) includes a first IDT (111), and a pair of IDTs (112) comprising a second IDT and third IDT. The first IDT (111) has a pair of first divided comb-shaped electrodes (111a) for which the comb-shaped electrodes on the side farther from the unbalanced terminal (10) are divided along a central axis (x). The pair of first divided comb-shaped electrodes (111a) is connected to the second elastic surface wave filter part (12) by the inter-stage wires. The comb-shaped electrodes of the second IDT and third IDT (112) on the side farther from the unbalanced terminal (10) are connected respectively to ground wires arranged outside of the inter-stage wiring. |
