Patent ID: 6708022
Filing Date: 2004-03-16
Classification: H03F,H04B

Abstract:
A power amplifier system comprising:a Schottky barrier gate metal semiconductor field effect transistor (â€œMESFETâ€ ) having a source, a drain and a gate electrode, wherein the gate electrode is formed on a semiconductor region so as to form a Schottky diode between the gate electrode and the semiconductor region, and a gate current flows as a forward direction current of the Schottky diode by increasing a gate bias voltage to be supplied to the gate electrode, and wherein materials of the gate electrode and the semiconductor region are arranged so that, when a gate bias voltage to be supplied to the gate electrode is greater than or equal in value to 0.65 volts (V), the gate bias voltage causes a gate current value per gate electrode width of 100 micrometers (&mgr;m) of at least 100 microamperes (&mgr;A); and a bias circuit arranges to receive a unipolar power supply, and to provide the gate bias voltage to be supplied to the gate electrode, wherein the MESFET amplifies an input signal superposed with the gate bias voltage provided from the bias circuit.