GrenTech, as one of the leading 5G RF filter manufacturers, is specialized in producing base station RF products. Due to the introduction of the Massive MIMO function, the installation position of the RF filters for 5G base station has changed greatly. At the same time, the base station filter is required to be miniaturized and lightweight. The miniaturized metal filter has become an important RF front end module for the 5G base station in terms of filter products.