Design And Verification Of RF Front-End For 8-Transmit-8-Receive Channel Simulator In 39GHz Frequency Band

Channel simulators are capable of simulating real-world wireless channel environments,improving product testing efficiency while reducing testing costs.However,there is a lack of Multiple-Input Multiple-Output channel simulators that support millimeter-wave frequency bands,and some channel simulators require frequency extension options to extend frequencies to the millimeter-wave frequency bands,which cannot be directly applied to test millimeter-wave products.As an important component of the MIMO millimeter-wave channel simulators,the millimeter-wave frontend is highly related to the performance of channel simulators,which is utilized to achieve the mutual transformation of multi-channel millimeter-wave signals and intermediate frequency signals.Its design challenges lie in multiple RF channels,high linearity requirement,and low phase noise.This thesis focuses on the millimeter-wave front-end of a 39 GHz 8×8 channel simulator,and the main research work includes the following three aspects:Firstly,this thesis analyzes the key performance measurements of the RF front-end of the 39 GHz 8×8 channel simulator.Based on millimeter-wave base station backhaul scenarios,millimeter-wave channel models,and 3GPP standards,the key performance measurements of the channel simulator are analyzed.Subsequently,this thesis analyzes the impact of key measurements of the millimeter-wave front-end on testing performance,and proposes the implementation method for the RF front-end of the 8x8 channel simulator.The key measurements of each component are also explained.Secondly,this thesis designs the 8-channel down-conversion and up-conversion modules,and the low phase noise local oscillator circuit.The second-order downconversion superheterodyne structure is selected as the solution for multi-channel up/down-conversion in the millimeter-wave front-end first.Then,this thesis implements the 31～33.5GHz low phase noise local oscillator for frequency conversion in the 39 GHz band,by utilizing the direct frequency synthesis technology to extend output frequency of the phase-locked dielectric resonator oscillator.Finally,proper components are selected to implement the 8-channel down-conversion and up-conversion modules,and the low phase noise local oscillator circuit of the millimeter-wave front-end,according to the design plan.Thirdly,this thesis tests and analyzes key performance measurements under laboratory conditions by building a testing platform.The performance of downconversion,up-conversion,and low phase noise local oscillator of the millimeter-wave front-end are evaluated firstly,followed by the joint testing of the up-conversion and down-conversion,and finally,the system signal-to-noise ratio is tested to evaluate the system functions.The results demonstrate that when the input power is-10 d Bm,the output power is-20 d Bm,and the channel bandwidth is 224 MHz,the joint in-band fluctuation of the up-conversion and down-conversion of the channel simulator millimeter-wave front-end is less than 2d B,and the phase noise at 10 k Hz frequency offsets is less than-94 d Bc/Hz.Besides,the system signal-to-noise ratio reaches 48.4d B under the 112 MHz channel bandwidth and 4096 QAM modulation.These proves the effectiveness of the channel simulator design.Based on the second-order conversion superheterodyne structure,as well as the approach of mixing the base frequency source and phase-locked dielectric resonator oscillator and then doubling the frequency,this thesis implements the RF front-end of the39 GHz 8×8 channel simulator,providing effective instances for the design of millimeterwave MIMO channel simulator front-ends.