Design Of 0.7-7GHz RF Receiver Front-End Chip

Nowadays,the wireless communication market rapidly developed and there emerged a variety of wireless communication standards.As a result of this,multi-standard and multi-band chip design has become an important research direction.Each alternative band in IMT-A ranges between 0.7 to 7GHz.0.7-7GHz is also compatible with part of the UWB standard band.This paper researched and designed a 0.7-7GHz RF receiver front-end chip,including LNA(Low Noise Amplifier)and Mixer.First,based on the resistive-feedback topology,this paper designed a 0.7-7GHz wideband LNA.The proposed LNA adopts self-biased resistive-feedback structure to realize input matching and applys shunt-peaking and negative feedback technology to bandwith extension.Shunt-peaking inductor with a PMOSFET is choosen as the load to boost the gain while maintain low NF at high frequencies,which can further expand the bandwidth.LNA uses two-stage common-source amplifier with shunt-peaking load to make the gain stable on a scale of 0.7-7GHz,meanwhile,keep NF low enough within the whole band range.Design of PCB and test was accomplished with good results as follows:2.5dB<NF<3.1dB,25dB<S2i<27dB,-15dB<S11<-9.8dB,-33dB<S22<-6.4dB,IP1dB>?26dBm,IIP3>-15dBm?Second,a 0.7-7GHz noise-cancelling LNA was proposed on the basis of noise cancellation techniques.The LNA employs negative feedback technology to achieve wideband input matching and applys noise cancellation techniques to cancelling noise of the circuit,which will improve LNA's noise performance and realize a single-ended to differential conversion.Current-reuse technique is used to enhance input transconductance and loop gain,improve noise performance,and reduce the limitation of low voltage.LNA's noise performance can be further ameliorated through feed-forward noise cancellation technique.Cross-coupling balanced-Buffer is used to optimize the differential output performance.The results of post-simulation are shown below:Gain=19.5dB,NF<2.34dB,S11<-11dB,S22<-12dB,IP1dB>-19.2dBm.Next,this paper put forward a circuit configuration of wideband passive Mixer,including passive switch pairs,LO-buffer,and IF amplifier with adjustable gain.Linearity and noise performance of the Mixer can be improved by a reasonable design of size and bias of the passive switch pair.LO drive circuit amplifys the LO signal,which can optimize the switch working state,improve Linearity and noise performance,provide some isolation,and reduce LO leakage.Furthermore,IF amplifier is characterized by adjustable gain and low pass filter function.This passive down-Mixer's intermediate frequency band equals to 300MHz,conversion gain adjusts between 10dB and 4dB,(DSB)NF<10dB,IP1dB>-7.9dBm.Finally,this paper will accomplish the design of 0.7-7GHz RF receiver front-end chip by cascading 0.7-7GHz wideband LNA and wideband passive Mixer.At the same time,layout design and post-simulation is finished.The simulation results of RF receiver front-end shows that S11<-10.58dB,input matching is satisfactory and gain adjusts between 34 dB and 40 dB.Other parameters are as follows;BW=300MHz,IP1dB>-36.7dBm,IIP3>-28.6dBm,NF<4dB.Post-simulation result meets the requirements of design index.