Design Of High Linearity RF Front End Circuit For ISM Band

Since the American federal communications Commission defines the ISM frequency band,This band has no restrictions on users,so users can use this without permission,what’s more it’s non-renewable spectrum resources,so the utilization of ism band is a hot spot.First,the RF front-end circuit of this thesis is based on the architecture of zero-If receiver.firstly in this thesis,i analyse several structures of low noise amplifier and down-conversion mixer,then describe the advantages and disadvantages of each circuit,finally according to the research goal,the circuit structure of high linear RF front-end circuit is proposed.The proposed low noise amplifier uses the technology of cross-coupling capacitance to improve the gain,and the technology of the pcsmin technology not only improves the noise performance but also reduces power consumption.The simulation results show that the noise figure NF is 2.24 dB,the gain S21 is 21.78 dB,and input 3rd order interrept point IIP3 is 2.64 dBm.The type of the proposed down-conversion mixer chooses the type of current-driven passive mixer,in the transconductor stage,the current-reuse structure reduces the power consumption and increase the gain of the circuit,the switch stage of the mixer is still driven by 50% duty cycle of square wave.two series PMOS transistors work as switch stage,not only save the area of the map,but also optimize noise performance.Transimpandance amplifier adopts current amplifier with resistance load,and the techniqueof the transconductance enhancement guarantee that current source amplifier has a very small input resistance,which increase the frequency mixer linearity.The simulation results show that gain is 12.0dB,the input 3rd interrept point IIP3 is 8.78 dBm,Double sideband noise DSB NF is 10.8 dB,power consumption is 5.81 mW,the various performance parameters is improved.Finally,the layout of the whole RF front-end circuit is plotted by cadence software,and the parameters are extracted and simulated.At the situation of the tt process corner and 27 ?C normal temperature,the simulation shows that the gain is 34.6 dB,the DSB NF is 3.71 dB,the power consumption is 22.1mW,and the input 3rd order interrept point IIP3 is-8dBm.Permance meets the design requirements.