PURPOSE: To enable the flattening of the gain characteristic, enlargement of band, and improvement in isolation characteristic by a method wherein a line is reduced in characteristic impedance and terminated at the characteristic impedance in an AC manner.
CONSTITUTION: Alumina of γ10 or the like is used for a dielectric substrate 1 to realize the characteristic impedance of a signal line 3 at 50Ω or 75Ω; whereas, a substrate 9 of high dielectric constant is used for a power source feed substrate to reduce the characteristic impedance of a power source feed line pattern 4. Actually, γ3,000 is being realized, and the characteristic impedance can be reduced to approx. 1Ω if the line width is 1mm and the substrate thickness is 0.2mm. Besides, adhesion of respective substrates can be realized satisfactorily with no problem even through the thermal process during chip assembly by the use of Ag paste of polyimide series or the like. Resistors 10 terminate the feed line pattern 4 at its characteristic impedance in an AC manner, and are formed by a thin film or thick film technique.
ISHIHARA NOBORU
OBARA MAMORU
