Abstract: In this paper the design of two low noise amplifiers proposed for WiMAX applications is presented. The two low noise amplifier topologies implemented are: (1) cascoded common source amplifier, (2) Shunt feedback amplifier. The amplifiers are implemented in a standard 180nm CMOS process, and are operated with a 1-V supply voltage and 5.9GHz frequency, the cascoded LNA achieved the best performance with a simulated gain of 15.7dB and noise figure of 1.85dB. The Low noise amplifier has been simulated using cadence spectre.