HIGH FREQUENCY AMPLIFIER

摘要

PURPOSE:To suppress positive feedback and to prevent oscillation by arranging a shield member connecting to a ground side and isolating both input and output terminals in terms of high frequency to the middle part of the input and output terminals of an amplification active element mounted on a circuit board. CONSTITUTION:The active element 10 is soldered to the input terminal 11 and the output terminal 12 at a part separating a conductor 24 of a microstrip 21 where a ground conductor 23 and a strip conductor 24 are arranged opposite via a dielectric board 22. Moreover, ground terminals 13a, 13b of the element 10 are connected to an earth pattern 25 clipping the element and bridged by the shield member 14. The height of the member 14 is formed nearly equal to the height up to the inside of a case 20 to suppress the radiation caused near the output terminal 12 bypassed to the input terminal 11 along the surface of the board 22 and the oscillation due to positive feedback is prevented.