Research On The Rf Components Of Millimeter-wave Nonsymmetrical System

In recent years,with the rapid development of the fifth-generation mobile communication(5G)technology,the millimeter-wave has attracted more and more attention due to its good characteristics,such as large bandwidth,low delay and high capacity.At present,5G millimeter-wave massive MIMO transceiver system mostly adopts the hybrid multi-beam architecture,but the architecture has some problems such as low frequency efficiency,narrow coverage range,and low power efficiency.The traditional full-digital architecture in millimeter wave band,has some problems such as high complexity,high cost and large power consumption.Recently,an asymmetric millimeter-wave massive MIMO system is proposed by the state Key Laboratory of millimeter Wave in Southeast University,which will combine the advantages of hybrid multi-beam and full-digital.The idea of the asymmetric architecture is that the transmitter has more full-digital channels,the receiver has less full-digital channels;the transmitter and the receiver use separated antenna array.The transmitter with more full-digital channels can make full use of the large transmitter array,obtain higher power efficiency.The receiver with less full-digital channels can significantly reduce system complexity,power consumption and cost.The full-digital architecture can provide a wide range of coverage.Because the antenna array of the transmitter and the receiver are separated,excellent isolation can be achieved in the millimeter wave band,and moreover,the antenna RF switches can be removed for lower noise figure and higher power efficiency.According to the idea of asymmetry,this thesis uses highly integrated chip to design an eightchannel millimeter-wave transmitting front-end and a four-channel millimeter-wave receiving frontend.These RF front-ends,including up and down conversion circuits,local oscillator modules,can support the full-digital implementation.The eight-channel transmitting can realize 8*8 massive planar array steadily.The four-channel receiving can reduce the volume,cost and power consumption,and has a high frequency spectrum efficiency.The asymmetric millimeter-wave transceiver front-end in this thesis works at 26GHz and the signal bandwidth is 400MHz.In order to suppress the interference of the image signal,the IF frequency band is selected at 3-4GHz.According to the management of the IF frequency,the RF local oscillator circuit is developed with excellent performance:-83.038dBc/Hz@100Hz,-100.02dBc/Hz@1kHz,-104.57dBc/Hz@10kHz,107.18dBc/Hz@100kHz,the integrated phase noise of the RF local oscillator is only-51.3dBc.The test results show that the local oscillator circuit has good performance.The thesis completes the design of multi-channel millimeter-wave transmitter and receiver front-end through PCB design.The test results show that the linear transmit power of the single-channel millimeter-wave transmit frontend is about 3dBm,the gain flatness is less than 1dB,the EVM degradation of the 400MHz 5G NR signal is about 3%,and the ACPR is less than-35dBc,which is in line with the 3GPP TS38.141 specification;the NF of the single-channel millimeter-wave receiving front-end is about 8dB,the gain flatness is less than 1.5dB,and the EVM degradation of the 400MHz 5G NR signal is about 2%,which also meets the specifications of 3GPP TS38.141.