In this paper, we optimized the performance of a 2.4 GHz variable gain low-noise amplifier for WLAN applications which provides high dynamic range with relatively low power consumption. First, the differential evolution algorithm was used to optimize the width of input transistors, then the tunable on-chip switching stage method was applied to control the amplifier gain when the input signal increases. The optimization was performed in terms of gain, noise figure (NF), IIP3 and power dissipation. The LNA has achieved a variable gain from 16.55 to 20.45 dB with excellent NF between 1.63 and 1.74 dB. Furthermore, the proposed circuit achieves a third order input intercept point of 6.6 dBm. It consumes only 10 mW from a 1.5 V supply.
