Research And Verification On Key Techniques Of 5G Terminal Wide-coverage 4×4 RF Circuits

At present,the 5G commercialization process is continuously advancing,and the 5G terminal chip is one of the keys to the commercialization of 5G.In order to complete the design of 5G terminal baseband chip,a prototype platform needs to be built for verification.The prototype platform consist of two parts,namely baseband and RF.In terms of this aspect,large bandwidth,multichannel and wide frequency coverage are the main challenges of RF circuits.According to 3GPP Release15 standard,the paper studies and verifies the key technology involving the 4×4 RF circuit of 5G terminal within the frequency range of 2.6GHz~5GHz.The specific work contents are summarized as follows:Firstly,the performances of superheterodyne architecture,Zero-IF architecture and Low-IF architecture were demonstrated in detail,in which their advantages and disadvantages were comparatively analyzed.Combined with the development demand of 5G terminal chip and the main challenges of 5G terminal RF circuit,the hybird architecture was determined to be adopted for the RF circuit.Specifically,superheterodyne architecture was utilized for receiving circuit,while the design plan of Zero-IF frequency architecture and superheterodyne architecture was applied for transmitting circuit.Secondly,according to the 3GPP R15 standard,the specific requirements of 5G terminal RF circuit were clarified on the basis of the network access requirements of domestic operators.Then,the key parameters of RF circuit,such as the receiving and transmitting EVM,harmonic suppression,ACPR,sensitivity,dynamic range and noise figure,were analyzed in detail.Based on the analysis results,the RF circuit architecture was designed,and appropriate RF devices were selected to complete the detailed design of amplification filter unit,frequency conversion unit,clock unit and baseband interface unit.Thirdly,the RF front-end test environment and system test environment was built.The test results revealed that in the RF front-end test environment,the transmitting EVM of 256 QAM was lower than 3.5% while the receiving EVM was below 2% at the data bandwidth of 100 MHz.In the system test environment,the downlink peak rate of the physical layer in the outer field was kept at 658.081 Mbps,while that of the physical layer in the inner field was kept at 1.11 Gbps.Finally,in view of the actual test results,suggestions were proposed for the subsequent design of 5G RF circuit.In the paper,a 5G terminal wide-coverage 4×4 RF circuit is designed and implemented,with frequency coverage ranging from 2515MHz~2675MHz,3300 MH ~3600MHz and 4800MHz~5000MHz.The maximum bandwidth is 100 MHz,and maximum transmission power is 23dBm/100 MHz,and all three frequency bands support 4-channel sending and 4-channel receiving.As a part of the 5G terminal chip verification platform,the design plays a certain role in the verification of 5G terminal chip,and provides certain reference value for the integrated design of 5G terminal RF circuit.