Investigations On Rf Receiver For Millimeter-Wave 5G Mobile Communications

With the development of mobile and wireless communication systems,the requirements of data rate,delay and data throughput are also increasing rapidly.The traditional communication technologies are becoming more and more difficult to meet the growing demands because of the crowded spectrum and the limited traditional technology.The 5G communication system,as the latest and developing technology,could improve the spectrum efficiency,transmission rate and efficiency to a new level compared with the traditional communication systems,as well as improvement in many other aspects such as the system security,transmission delay,user experience and coverage.There are many key technologies for 5G such as massive MIMO,millimeter waves,FBMC(filter bank multi-carrier)full duplex and Ultra-dense network technology,etc.This paper mainly focuses on a compact millimeter wave massive MIMO RF receiver which could be typically applied to 5G systems.The superheterodyne architecture is chosen to design this system and 16 channels with 256 antennas elements worked on Q-band are designed in this system.Two kinds of antennas are designed for each of the receiver channel.One is 4*4 patch antenna which are integrated in the bottom layer of each RF board,and the other are horn antennas which keep the same size as 4*4 patch antennas and fed by the patch in the bottom layer of each RF boards.The RF boards are designed using multi-layered structure and highly-integrated downconverter chips for the sake of the smaller size of 20mm*20mm and the better heat dissipation.In addition,other circuits are also designed for the measurement of signal channel such as the Intermediate frequency amplifier circuits,LO frequency amplifier circuit,LO frequency power divider circuit and power supply circuit.The performance of single channel receiver is measured with gain of 26dB;gain flatness of 0.12dB in a bandwidth of 100MHz;input 1dB compression point of-5.7dBm;third-order intercept point of 5.88dBm in the radio frequency of 42GHz.The EVM of this system is better than 1.84%with the symbol rate of 50Msps and the modulation of 256-QAM.