| 摘要 |
<p>A surface acoustic wave filter device comprises a surface acoustic wave filter chip (3) disposed on the upper surface of a substrate (1), input and output conductor patterns (5, 5 min , 6, 6 min ; 35, 35 min , IP, IP min , OP, OP min , 36, 36 min ; 65-1, 65-2, 66-1, 66-2) provided on each of the upper and lower surfaces of the substrate, and conductor patterns (7; 37, 37 min ; 57, 57 min ; E 67) for earth provided on each of the upper and lower surfaces of the substrate so as to surround the input and output conductor patterns on that surface in order to prevent an electromagnetic coupling between the input and output conductor patterns, whereby the out-of-band rejection not smaller than 40 dB is obtained in an operating band not lower than 400 MHz.</p> |
