RF Front End System Design Based On High Linearity And Low Noise

With increasing needs of the application,progress of technology,and improvement of integration level,the receiver chip calls for much stronger demand in performance.As the property of traditional receiver cannot fit for the needs of people,the breakthrough of the limitation of receivers becomes the targets between circuit designers.Among the performance of receivers,noise figure and linearity is the basic and the most important concepts in the evaluation of receivers.However,the consideration of noise figure and linearity is always in conflict,which should do a trade-off between these two targets.For the requirement of high linearity and low noise,this paper makes an investigation of performance extremity of RF front end,with linearity and noise figure to be analyzed from the aspects of theory and simulation.In the design of receiver's RF front end,mixers and trans-impedance amplifiers are the main modules in the consideration.For mixers,this paper mainly concentrates on the double-balance passive mixer,with its gain,resistance,noise and linearity in the control of the local oscillation of different duty cycles,and the problem in simulating IIP3 is to be explained and solved through the theory in newest papers.For trans-impedance amplifiers,this paper gives the analysis in gain,resistance,noise and linearity based on the classic model of amplifiers.And two kinds of high-linearity trans-impedance amplifiers is to be introduced in this paper with their theory deduction.On the basis of mixers and trans-impedance amplifiers,three structures of high-linearity RF front ends are proposed,with detailed analysis and derivations of input matching,gain,noise figure and linearity.In the end,the structure of the cascade of the mixer and the trans-impedance of RF front end is chosen to be realized in this paper,with simulation results in different process corners.