Patent ID: 7337547

Claim:
A high frequency switching circuit device for allowing at least one of a number of high frequency signal paths to conduct and for cutting off the rest, comprising: a compound semiconductor substrate; a number of switching elements which are made of metal-semiconductor field effect transistors formed on said compound semiconductor substrate and which interrupt said number of high frequency signal paths respectively; a number of control voltage input terminals for individually supplying a number of control voltages to said number of switching elements; and a diode logic circuit which is made of a number of diodes that are formed on said compound semiconductor substrate as metal-semiconductor Schottky junctions and which synthesizes logic of said control voltages that are inputted into said number of control voltage input terminals, wherein: a logic synthesis voltage that is outputted from said diode logic circuit is supplied to said number of switching elements as another control voltage, each of said number of switching elements is formed of a series switching element that has been inserted into each of said number of high frequency signal paths and a shunt switching element that is connected between each of said number of high frequency signal paths and the ground, said diode logic circuit outputs the logical sum of at least two control voltages of which the combination differs for each of said number of switching elements as the individual logic synthesis voltage, said number of control voltages are individually supplied to the gate electrode of each series switching element of said number of switching elements, and said individual logic synthesis voltages that are outputted from said diode logic circuit are supplied to the gate electrode of each shunt switch element of said number of switching elements as said other control voltage, respectively.