| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter device capable of simplifying circuit configuration, downsizing, and achieving low loss.SOLUTION: In a filter device, a low pass filter 4 and a high pass filter 5 are connected in series, and the low pass filter includes: first acoustic resonators 11a to 11c having resonance frequency and antiresonance frequency; first inductors 12a and 12b connected between a signal line and a ground potential; and first capacitive elements 13a and 13b connected to the first inductor in series. The high pass filter includes: second inductors 21a and 21b; second capacitive elements 22a and 22b connected to the second inductor in parallel; and second acoustic resonators 23a to 23c. A first attenuation band by the antiresonance frequency of the first acoustic resonators 11a to 11c is provided at low-frequency side of a passband and a second attenuation band by the resonance frequency of the second acoustic resonators 23a to 23c is provided at high-frequency side of a passband.SELECTED DRAWING: Figure 1 |
