| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave branching filter which is easily produced with excellent mass-productivity and by which low profile is realized a surface by face-down connection of an acoustic wave element, with little characteristic deterioration. SOLUTION: The branching filter is provided with a first surface acoustic wave filter element 1 with a transmission frequency as a pass band and with a reception frequency as a block band and the second surface acoustic wave filter element 2 with the reception frequency as the pass band and with the transmission frequency as the block band. The first and second filter elements 1 and 2 are connected by phase-down to a base board 10 via each metallic bump 3, concentrated constant circuit elements 15 are mounted on at least one surface of an upper base board 20 being different from the base board and, then, the base board 20 is joined with the upper base board 20 via a frame shape intermediate base board 12. |
