Abstract: An X-band low noise amplifier (LNA) module is designed and manufactured successfully,and an effective method for adjusting the gain flatness of the module is presented.The method entails placing several parallel resonant circuits between two low noise amplifier chips,providing different resonant frequency points at lower frequencies outside of the working band.It reduces the gain of the lower frequencies of the working band.The gain compression can be controlled by resistors added in the resonant circuits.As a result,flat gain is obtained using this method.This X-band LNA module shows a gain flatness of less than ±0.34dB,a noise figure less than 1.84dB,and a gain higher than 35dB.

Key words: X-band,  LNA,  gain flatness