A novel circuit is presented to extend the bandwidth of an ultra-wideband (UWB) low-noise amplifier (LNA). The circuit removes the series resistor in the shunt-peaking method. Consequently, the DC current can be increased to benefit from larger S21. A differential common-gate LNA using the presented circuit is implemented in a CMOS 0.18-μm technology. The LNA operates from 4.33 GHz up to 13.9 GHz while S_21 is 11.3±0.5 dB and S_11 is less than -10 dB over the whole of the bandwidth. Post-layout simulation shows the minimum noise figure (NF) of 3.84 dB and power dissipation of 2.5 mW.