| With the increasing shortage of spectrum resources,there is an urgent need for higher frequency band,larger bandwidth and higher rate to meet the transmission requirements between the base station and the network.At present,71-76 GHz and 81-86 GHz in the E band can provide up to 5GHz bandwidth respectively,and the single-frequency bandwidth can reach 2.5Gbps.Moreover,the atmospheric attenuation in the E band is small,so it has a great application prospect and engineering value.This paper introduces a wireless communication transceiver front end working in E band.This paper based on the millimeter wave itself characteristics and advantages of wireless communication,at home and abroad are introduced in the E band wireless communication has made some achievements,after analysis,this paper introduces several kinds of applied in millimeter wave radio transceiver structure and frequency synthesis technology,according to the objective index requirements and technical characteristics of the subsystems of the transceiver front-end can be divided into 1 and 2,a total of two subsystems,two sub-systems of design basic same,all in accordance with the modular design method of the transceiver front-end is divided into frequency source module,intermediate frequency module,the millimeter-wave transceiver module and power supply and signal processing module,a total of four modules.The transmitting frequency of millimeter wave in subsystem 1 is 83GHz±0.5GHz,and the receiving frequency is 74GHz±0.5GHz.The transmitting frequency and receiving frequency of millimeter wave in subsystem 2are opposite to those in subsystem 1.The transmitting link adopts a single-frequency upconversion structure,and the baseband signal frequency is 2.6GHz±0.5GHz.The local oscillator signal generated by PLL is up-converted with the baseband signal after 6 times the frequency,and the millimeter-wave transmitting signal generated is sent to the transmitting antenna after the three-stage amplification structure.The receiving link adopts the structure of single-frequency down conversion,and the local oscillator signal generated by PLL is converted down to 0.8GHz±0.5GHz with the received millimeterwave signal after 6 times of frequency,which is processed by the IF module and then sent to ADC for processing.This paper introduces the specific design process and circuit implementation process of each module in detail,and carries out cascading test on the transceiver link in the case of input single carrier signal,and then carries out EVM and constellation test on the74 GHz and 83 GHz transceiver systems in the case of input baseband signal.The test results show that the phase noise of local oscillator signal produced by frequency source module is better than-93 dBc/Hz@1k Hz,-99 dBc/Hz@10k Hz,-103 dBc/Hz@100k Hz,-122 dBc/Hz@1MHz.After transmitting link cascading,the output power and output 1dB compression point are greater than 20 dBm and 21 dBm respectively,the in-band power flatness is less than 2dB,the gain of receiving link is greater than 60 dB,the noise coefficient is lower 6dB,and the gain flatness is basically less than 2.5dB.The input baseband signals are modulated by QPSK,16 QAM,64QAM and 128 QAM respectively.When the power of millimeter wave transmitting signal is back 10?12dB,the EVM index of 74 GHz and 83 GHz transceiver signals deteriorates less,and the whole communication system can meet the requirements of different modulation modes. |
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