Patent ID: 8431973

Claim:
A high frequency semiconductor device comprising: a field effect transistor including a semi-insulating substrate, gate finger electrode, a source finger electrode, and a drain finger electrode which are disposed on a first surface of the semi-insulating substrate and each of which has a plurality of fingers, a plurality of gate terminal electrodes, a plurality of source terminal electrodes, and a drain terminal electrode which are disposed on the first surface of the semi-insulating substrate, said plurality of gate terminal electrodes tied to respective plural fingers of said gate finger electrode, said plurality of source terminal electrodes tied to respective plural fingers of said source finger electrode, and said drain terminal electrode tied to plural fingers of said drain finger electrode, a VIA hole disposed under the source terminal electrode, and a ground electrode which is disposed on a second surface of the opposite side of the first surface of the semi-insulating substrate, and is connected via the VIA hole to the source terminal electrode; an input circuit pattern and an output circuit pattern which are disposed adjoining of the field effect transistor; an input connecting element configured to connect the plurality of the gate terminal electrodes and the input circuit pattern; and an output connecting element configured to connect the drain terminal electrode and the output circuit pattern, wherein a phase of a transmission signal of the input connecting element is matched by adjusting an inductance distribution of the input connecting element.