| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave high frequency filter capable of reducing the insertion loss and also obtaining a high attenuation at out-band. SOLUTION: The surface acoustic wave high frequency filter comprises surface acoustic wave resonators 52 to 54 whose input terminals and output terminals are connected in series with each other to form a signal line and surface acoustic wave resonators 38 to 40 one of an input terminal and an output terminal of each of which is connected to the signal line and the other of the input terminal and the output terminal of each of which is connected to ground, the surface acoustic wave resonator 52 includes interdigital electrode surface acoustic wave transducers 8, 9 connected in series, the surface acoustic wave resonator 53 includes interdigital electrode surface acoustic wave transducers 10, 11 connected in series, and the surface acoustic wave resonator 54 includes interdigital electrode surface acoustic wave transducers 12, 13 connected in series. Then the impedance of the surface acoustic wave resonators 52 to 54 connected in series with each other to form the signal line is four times that of the surface acoustic wave resonators 38 to 40 connected in parallel with the signal line. COPYRIGHT: (C)2007,JPO&INPIT
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