Patent ID: 8159315

Claim:
A substrate for mounting one or more filters comprising: a first insulation layer; and a second insulation layer which has a thickness that is greater than the thickness of the first insulation layer, the second insulation layer being placed below and laminated to a the first insulation layer, wherein the substrate has a first region and a second region, wherein the first region of the substrate further comprises: a first connection line layer on the first insulating layer, the first connection line layer having at least one transmission line for connecting the filter; and a ground layer interposed between the first insulation layer and the second insulation layer, the first insulation layer having a thickness which satisfies a characteristic impedance of the transmission line of the first connection line layer in a range 0.1 to 50 ohms, the characteristic impedance being determined by the thickness and a dielectric constant of the first insulation layer and a width of the transmission line of the first connection line layer, and wherein the second region of the substrate further comprises: a second connection line layer on the first insulating layer, the second connection line layer having at least one transmission line; and a ground layer disposed below the second insulation layer, defining a characteristic impedance of said transmission line of the second connection line layer that is different from the characteristic impedance of the transmission line of the first connection line layer, said ground layer being absent between the first insulation layer and the second insulation layer.