In this paper design, fabrication and measurement of a GaN HEMT based Monolithic Microwave Integrated Circuit (MMIC) Low Noise Amplifier (LNA) is presented. 12-Term equivalent circuit modeling is exacuted. Inductive source feedback topology is used to obtain low Noise Figure (NF) with appropriate input return loss. The gain of this design is higher than 25 dB, input return loss is better than 13 dB and NF value is 1.6 dB in S band. This work is only 3 x 5 mm. LNA has 28.1 dBm output third-order intercept point. Output power at 1-dB compression point is 18.2 dBm. Group delay is less than 0.3 nanoseconds. Due to superior properties of GaN technology, without NF performance degradation GaN LNA enables to high input power handling (P in is 20 dBm, CW, 10 mins).