PURPOSE: To provide a surface acoustic wave device using an Li2B4O7 capable of eliminating spurious radiation at a high frequency side at the outside of its band even when the film thickness of interdigital electrodes is made thick.
CONSTITUTION: In the surface acoustic wave device in which an interdigital electrode 20 having a couple of interdigital electrodes 22, 24 with combination of electrode fingers 22a, 24a on a tetraborate lithium single crystal substrate 10, a distance (d) of a couple of short bars 22b, 24b interconnecting the electrode fingers 22a, 24a of a couple of the interdigital electrodes 22, 24 is selected within a range of -100(h/λ+7≤d/λ)≤-120(h/λ)+11.9 when a normalized film thickness h/λ of a couple of the interdigital electrodes 22, 24 is 1.5% or over.
MASAKI MITSUYUKI
SAKAGAMI TOMOKO
