PURPOSE: To make it possible to apply a DC bias to a mixer diode from outside by insulating in terms of DC a part of an earth conductor forming a coplanar line as well as a fin line.
CONSTITUTION: Fine lines 5a and 5b are provided on the surface of a dielectric substance put on a housing 1a, and mixer diodes 10a and 10b are set close to the junction part between the fin lines and a coplanar line. With a fin line balanced mixer of such a constitution, metallic wires 11a∼11c functioning as mode filters are used to connect an earth conductor 6a and an earth conductor 6b via chip capacitors 14a∼14d. Thus the conductor 6b is insulated in terms of DC from the housing 1a by the dielectric substance, and at the same time the center conductor of the coplanar line is insulated in terms of DC from an external circuit by a capacitor 16d. Thus it is possible to apply an external bias to diodes 10a and 10b through bias terminals 20a and 20b respectively.
TAKEDA FUMIO
MATSUNAGA MAKOTO
