| 摘要 |
PROBLEM TO BE SOLVED: To always secure a large frequency variable range without the aid of a set side substrate pattern and to stabilize ground pattern and to reduce power noise by means of providing a wide ground pattern by constituting a hollow layer which is made into a cavity by removing a substrate peripheral part in an inner layer held by a ground pattern layer and a wiring layer on a multilayer substrate. SOLUTION: In a multilayer substrate where a circuit constituting an oscillator is wired/mounted, a hollow layer 104 which is made into a cavity by removing a peripheral part is provided in an inner layer held by a back ground pattern layer 106 and a surface wiring layer 102 where element parts 103 are mounted and wired. The dielectric constant of air is small to a degree which is almost similar to vacuum. Parasitic capacity generated among the wiring pattern of an oscillation circuit part, a part electrode terminal and a ground pattern can be suppressed to be small and a wide frequency variable range can be secured in the oscillator provided with the hollow layer 104 between the wiring layer 102 and the ground pattern layer 106.
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