MICROWAVE AMPLIFIER

PURPOSE:To prevent residence of void and flux lump in a solder layer in the vicinity of a matching circuit by forming a soft board so as to be provided with a throughhole in the vicinity of the matching circuit. CONSTITUTION:Plural 1st throughholes 21 are provided to soft boards 8A, 9A, 10A close to matching circuits 11, 12, 13 at positions close to both sides of the circuits along the matching circuits 11, 12, 13 and plural 2nd throughholes 22 are provided to positions of the soft boards 8A, 9A, 10A parted from the matching circuits 11, 12, 13. Thus, since a pressure of a part in a molten solder layer 25 opposite to the throughholes 21,22 is lower than a pressure of the other part, a void 26 and a flux lump 27 are moved in the direction of the throughholes 21,22 and escaped upward through the throughholes 21, 22 finally as shown in an arrow 28. Thus, the void and flux lump are entirely avoided.