PURPOSE: To miniaturize a power amplifier section by imbedding an absorbing body of a resistive terminator into a heat sink of a power amplifier so as to use the heat sink in common thereby decreasing a heat sink mounting metallic fixture or the like in the heat sink structure of the resistive terminator used for a high frequency amplifier section of a communication equipment.

CONSTITUTION: An output from a power amplifier 20 on a heat sink 21 is inputted to an isolator 23 via a waveguide 25 and given to an output waveguide 29, then a resistive terminator 30 is imbedded in the heat sink 21 via a waveguide 32. Thus, a hole 33 has the same diameter as that of the waveguide 32, and an absorbing body 34 to absorb a radio wave is imbedded to absorb a reflected wave. Through the constitution above, a large amount of heat generated in the resistive terminator 30 is dissipated by an axial fan 28 and the heat sink 21 so as not to require an exclusive heat sink for the resistive terminator. Thus, a mount metallic fixture or the like is omitted and the power amplifier is miniaturized.