PURPOSE: To attain stable support, by providing a metallic film possible to be soldered to the back side of a piezoelectric substrate.
CONSTITUTION: An interdigital electrode 5 is formed on the surface of the piezoelectric substrate 2. The solderable metallic thin film 3 made of gold or silver is provided at one end at the back side of the piezoelectric substrate 2. A metallic film 8 made of aluminum not solderable is provided at a part of the back side of the piezoelectric substrate 2 not provided with the metallic thin film 3. The part of the metallic thin film 3 and a holder 1 are connected by using a solder member 4. Since the fixing is performed at one end, no filter characteristic is changed even if the holder 1 is deformed with temperature.
TANI ATSUSHI
KISHI SHIYOUICHI
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