| 摘要 |
<p>A ladder filter device includes elastic wave resonators with IDT electrodes. An apodization angleθin an IDT electrode of a series arm resonator in the ladder filter device falls within a range from about 2° to about 14° with respect to an elastic wave propagation direction. This arrangement provides a ladder filter device that has a smaller insertion loss in a low frequency side portion of a passing band.</p> |
