A novel Ku-band low noise amplifier with a high electron mobility transistor (HEMT) and a GaAs monolithic microwave integrated circuit (MMIC) has been demonstrated. Its noise figure is less than 1.9dB with an associated gain larger than 27dB and an input/output VSWR less than 1.4 in the frequency range of 11.7–12.2GHz. The HEMT and the microwave series inductance feedback technique are used in the first stage of the amplifier, and a Ku-band MMIC is employed in the last stage. The key to this design is to achieve an optimum noise match and a minimum input VSWR matching simultaneously by using the microwave series inductance feedback method. The BJ-120 waveguides are used in both input and output of the amplifier.