| 摘要 |
<p>A branching filter is a surface acoustic wave device in which a first filter having a relatively low bandpass frequency and a second filter having a relatively high bandpass frequency are connected to a common terminal. A junction-side resonator that is included in the second filter and that is connected in closest proximity to the common terminal is connected in series. The resonant frequency f sr of the junction-side resonator is higher than the center frequency f 0 , which is the center of the passband, of the second filter, and is more preferably set so as to satisfy the expression: f 0 + BW x 0.2 ‰¤ f sr ‰¤ f 0 + BW x 0.7, where BW is the bandwidth of the passband.</p> |
