Abstract: This invention discloses a monolithic microwave integrated circuit (MMIC) package with filtering property. The filtering action is inherent with the structure of the package. This structure overcomes the limitation of traditional packages, which can only transmit the signal without processing the signal. A specially designed surface-mountable structure is used in the input and the output terminals. Any impedance from this special structure can be compensated by the filtering structure in each port. The filtering structure is located between the input (or the output) structure and the die cavity in each port. The package also provides ground connection to the MMIC by means of metal-filled via holes connected to the surface mounting side.