Investigations On Receiver Technology For Millimeter Wave Multibeam Array

With the ever growing traffic explosion in mobile communication,millimeter wave communication technology will play a more and more important role in future wireless communication systems.Massive MIMO and millimeter wave communication are two key technologies of the fifth generation mobile communications(5G).In this paper,the receiver technologies for 5G millimeter-wave(mmWave)digital multi-beam array and mmWave phased array are studied.As for the 5G mmWave multi-beam receiving array,a 128 channel receiver array was designed in this paper.The system structure,RF front-end module,IF circuits and power supply module are introduced.Some modules and the whole system are tested.The tested results show that the gain of the IF circuit is greater than 20 dB and the gain imbalance between channels is less than 2dB.The gain of the RF front-end is greater than 25dB,and the gain flatness within 500MHz bandwidth is less than 1.5dB,and the gain imbalance between the 128 channels is less than 3dB.At the center frequency of 26 GHz,the EVM tested results of QPSK,16QAM,64QAM and 256QAM modulated signals with the symbol rate of 50Msps are 2.6%,2.2%,2.1%and 1.8%respectively.The SNR of the output signal is greater than 30dB.The beam scanning performance of the receiving system is tested and the results show that 16 receiving channels can achieve beam scanning range of ±50° with digital multi-beam technology.For the mmWave receiving phased array,a four-channel receiver for phased array is designed and implemented in chapter 4.The receiver has two down-conversion steps with a RF bandwidth of 2 GHz and an IF bandwidth of 500MHz.The receiver is working in Ka frequency band.The gain of the single channel is greater than 26dB and the gain imbalance between channels is less than 2dB.The gain flatness within 500MHz bandwidth is less than 2.5dB.The mirror suppression ability of the four channels is greater than 50dBc,and the EVM test results of QPSK,16QAM,64QAM and 256QAM modulation signals with 50Msps symbol rate are less than 3%.The beam scanning results pointing to 0,±3°,±5° are shown and the tested results of beam pointing are consistent with the simulated results.