| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that wirings for input/output cannot be isolated due to deterioration in attenuation and isolation in a blocking area of a surface acoustic wave filter, since equivalent wavelength of used frequency becomes small and resonance of electromagnetic wave propagated through the wiring of a package occurs. SOLUTION: A package for a surface acoustic wave filter comprises an insulating base substance 11, which has a recessed part 11a for mounting a surface acoustic wave filter element 17, and in which a frame-like metallized layer 14 is formed on the top surface of the peripheral part, and a lid body 15. The insulating base substance 11 comprises a ground conductor layer 12 in it. The metallized layer 14 is connected to the ground conductor layer 12 with a plurality of penetrating conductors 31 and side surface conductors 32, displaced with the interval not over sixteenth of equivalent wavelength of center frequency of a passing band of the surface acoustic wave filter element 17, in between. Resonance of electromagnetic waves propagated through an input/ output wiring 13 is suppressed, and deterioration in attenuation in a high-frequency blocking area and isolation between the input/output wirings 13 and 13 are improved.
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