In March 2021, in the fourth round of sanctions against Huawei, the United States clearly stipulated that as long as the device supplier used the technology of the United States, it could not supply 5G equipment to Huawei, and seized the \"throat\" of Huawei's 5G RF front-end chip supply chain.
At present, none of the filters that domestic manufacturers can make can completely get rid of the use of American equipment. To revitalize the industrial chain, a screw cannot be relaxed.