Low noise amplifier (LNA) performs as the initial amplification block in the receive path in a radio frequency (RF) receiver. In this work an ultra-wideband 3.1 10.6-GHz LNA is discussed. By using the proposed circuits for RF CMOS LNA and design methodology, the noise from the device is decreased across the ultra wide band (UWB) band. The measured noise figure is 2.66 3 dB over 3.1 10.6-GHz, while the power gain is 14 ± 0.8 dB. It consumes 23.7 mW from a 1.8 V supply. The input and output return losses (S11 & S22) are less than –11 dB over the UWB band. By using the modified derivative superposition method, the third-order intercept point IIP3 is improved noticeably. The complete circuit is based on the 0.18 μm standard RFCMOS technology and simulated with Hspice simulator