Design And Implementation Of Low-cost 5G Mobile Phone RF Circuit

At present,smart communication devices have been widely used.Meanwhile,mobile communication network technology has also been developed to the fifth generation.5G communication technology can provide network capacity and speed far exceeding 4G,and large smart mobile device manufacturers have launched a variety of 5G smart phones.However,for small and medium-sized enterprises,the complexity of 5G radio frequency circuits,high licensing fees required for the development of 5G smartphones and the cost of 5G test equipment have become a troublesome edge to enter the 5G field.In order to provide small and medium-sized enterprises with a high cost-effective 5G mobile phone radio frequency research and development guidance,this paper design and realize the RF circuit of 5G mobile terminal by combining the 3GPP's specification requirements for 5G mobile phones,previous generation of mobile communication mobile phone research and development experience,and using the relatively low-end 5G platform MT6873 as design platform,afterwards carries out matching debugging and calibration test by vector network analyzer and wideband radio communication tester respectively.First of all,this paper introduces the main features of 5G NR system,several key technologies in detail,and demonstrated the mobile phone RF indicators suitable for small and medium-sized enterprises.This RF circuits should support global Netcom and control its costs as much as possible.Then it combines them with the previous generation mobile phone radio frequency circuit framework to determine the 5G radio frequency circuit framework.This article also analyzes and evaluates the two key indicators of the maximum transmit power and receive sensitivity of the RF transceiver system through the link budget to give guidance to the RF circuit design.Finally,Media Tek MT6873 platform is used to design each RF front-end module and RF chip peripheral circuit of the mobile phone RF system,as well as the antenna RF switch circuit.After the entire RF circuit system is designed and implemented,the load-pull technology is used to debug and optimize the matching circuits of the power amplifier output and antenna back-end channel to RF performance is optimal and stable.As well as automatic frequency control,transmission power control and receiving path loss calibration of the radio frequency circuit of the whole machine,the radio frequency indicators between different complete units can meet the requirements of 3GPP indicators when it works normally and ensure the consistency during mass production.Finally,according to the 3GPP test specifications and index requirements,the key indicators of the main research frequency band in the mobile phone RF system are tested,and suggestions for the selection of 5G radio frequency comprehensive testers are given.This paper shows some test results of mid channels in the frequency band ENDC?7A?N78A.The test results show that the channel in the frequency band has a sensitivity of over-91.8 d Bm with 20 MHz bandwidth under different modulation mode.The maximum transmit power under different modulation mode is 23.01 d Bm,while also other key indicators were tested in detail,the test results fully meet 3GPP standards.