A New Linearity Enhancing Technique for Low Noise Amplifiers

In this paper a technique is proposed to enhance the linearity of low noise amplifier using nonlinearity of other components. This technique increases IIP3 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 with low noise figure is required. Linearity improvement by use of nonlinear components is the basic idea for IIP3 improvement of this LNA. Currents produced by two amplifiers having different linearity characteristics are fed to current subtractor which gives current having good linearity characteristics but having a lower gain. Simulations based on layout of proposed architecture show that this architecture increases IIP3 up to 10+ dBm and the circuit is suitable for low noise applications. Amplifier achieves a gain of 10.5dB, noise figure of 1.5dB and dissipates 14.5 mwatts power from 1.8 volts supply