| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave filter capable of establishing the specification of a spurious band which is of two times or three times as high as central frequencies without using any other filter for spurious specification, and realizing miniaturization and high performance. SOLUTION: A bridged T type surface acoustic wave(SAW) filter 20 is provided with a serial arm resonator (SR1) 21 having prescribed resonance frequencies, a parallel arm resonator (PR1) 23 having resonance frequencies almost matched with the inverse resonance frequencies of the serial arm resonator (SR1) 21, a serial arm resonator (SR2) 22 having prescribed resonance frequencies, an input terminal (IN) 25, an output terminal (OUT) 26, and ground terminals (E) 27 and 28. This T type acoustic surface wave filter is provided with an SAW resonator (BR1) 24 for bridging the input and output of the T type surface acoustic wave filter.
|
