A New Linearity Enhancing Technique for 802.11 b/g Low Noise Amplifiers

A new linearity enhancing technique is proposed to increase linearity of low noise amplifier using current subtraction technique. This technique increases IIP3 point of low noise amplifier without large increase in overall noise figure of LNA. This technique can be very useful for 802.11 b/g and Bluetooth applications where high linearity is required with a low noise figure. Current mirror circuit achieves the current subtraction, which is the basic idea for IIP3 improvement of this LNA. Current mirror circuit gives difference in the currents produced by two amplifiers having different characteristics. The LNA was designed to operate at 2.4 GHz. The proposed technique increases IIP3 up to 10+ dBm and is suitable for low noise applications. Amplifier achieves a gain of 10 dB, noise figure of 1.49 dB and dissipates 22 mwatts power from 1.8 volts supply.