The Research And Design Of Active Mixer For RF Front-End

Since the 21 st century,wireless communication technology has developed rapidly,and the demand for communication equipment has been expanding and the requirements are getting higher and higher.While the process size continues to decrease,wireless communication devices tend to be more integrated.In wireless communication devices,a radio frequency receiver is an important module that determines the performance of a wireless communication system.Among them,the mixer is an important module in the RF receiver,and the signal at the RF front end is very strong.Therefore,improving the performance index of the mixer is to improve the performance index of the entire RF front-end.Therefore,it is of great significance to study the mixer.In this thesis,after discussing the research status of the mixer,according to the classic Gilbert circuit structure of the active mixer,the performance index of the mixer: conversion gain,linearity and noise figure are introduced.The process completes the design and simulation of the following three active mixers:(1)A down-converting active mixer based on current multiplexing structure is designed.The circuit mainly improves the performance of the circuit through a current multiplexing structure and a dynamic current injection structure.The working voltage of this design is 1.2 V.The simulation of Cadence software shows that the conversion gain of the circuit is 25.4 dB,linearity(input third-order intercept point)is 26.04 dBm,the power consumption of the circuit is 8mW,and the noise figure is 7.78 dB.(2)A down-converting active mixer based on a trans-conductance coefficient correction structure is designed.The circuit adds a trans-conductance coefficient correction structure that allows for improved circuit gain and linearity.The circuit also has an inductor connected across the drain of the trans-conductance stage to reduce the noise effects of parasitic capacitance on the circuit.The simulation of Cadence software shows that the operating voltage is 1.2 V,the RF frequency is 2.4 GHz,the conversion gain is 28.4 dB,the linearity(input third-order intercept point)is 10 dBm,the power consumption is 6.68 mW,and the noise figure is 8 dB.(3)A down-converting active mixer based on a third-order trans-conductance coefficient cancellation structure is designed.The trans-conductance stage of the circuit uses a current mirror structure and a third-order trans-conductance coefficient cancellation structure.By setting the transistors to operate in different regions,the thirdorder trans-conductance coefficients of the tubes are eliminated from each other to improve the performance of the circuit.The simulation results of Cadence software show that when the operating voltage is 1.2 V,the RF frequency is 5.2 GHz,the conversion gain is 21.9 dB and linearity is 21.68 dBm,the power consumption is2.3 mW and the noise figure is 16.5 dB.