Analysis And Design Of High Linearity LNA Based On Volterra Series

The development of Software-defined-radio(SDR)has proposed requirement of broadband,low noise and high linearity of RF receiver.Low noise amplifier(LNA)is usually the first stage in a normal RF front end,as a result,the linearity of LNA has great influence on the whole linearity of receiver,especially when the power of signal is quite large.Nonlinearity of LNA mainly comes from the nonlinear transconductance of MOSFET.Thus,traditional linearization techniques focus on negative feedback,biasing transistor at good working zone or use parallel/series transistors to improve linearity of MOSFET and LNA.However,these techniques have drawbacks such as degrading the gain and noise performance of LNA,dependence on the structure of LNA,requiring off-chip bias voltage,and severely sensitive to process,temperature and source voltage.This paper introduced the development and calculation method of nonlinear circuit based on Volterra series.Popular linearization techniques are simulated and compared.A high linearity LNA is designed based on multiple gate derivative superposition method,and is simulated both in broadband and narrow band impedance matching.Besides,this paper designed a on chip biasing circuit for the high linear LNA,which helps the high linearity remain robust to process,temperature and source voltage.Simulation shows the method merely changes gain and noise performance of origin LNA,and linearity is improved by average 12 dB with temperature from-55 to 125 degree and three process corner under TSMC 180 um.