Wideband amplifier using fet.

摘要

The present invention concerns with a wideband amplifier concurrently receiving multi-channel signals in a predetermined frequency range and amplifying the received signals. In particular, the wideband amplifier is characterized in that as a semiconductor element employed in the amplifier, a field-effect transistors (11) is used, the transistor (11) having a substantially flat characteristic of mutual conductance to a voltage (VGS) between a gate and a source with respect to the center of an operation point for suppressing a second order distortion of an output of the amplifier. And, there is also provided a wideband amplifier wherein in case of inspecting a field-effect transistor, the second order distortion in a high frequency is guaranteed to be a constant value or less by accepting only the wideband amplifier having a predetermined or lower value of the difference between the mutual conductances to the applied voltages at an input terminal having a constant difference therebetween.