Overview of Base Station Requirements for RF and Microwave Filters

As is commonly acknowledged, the frequency spectrum is the most valuable resource in wireless communication, and filter is the key component for its efficient utilization. Filter solutions vary greatly in different base transceiver station (BTS) system. To be more specific, metal cavity filters are dominant in 4G macro BTSs, while dielectric filters and miniaturized metal cavity filters are widely used in 5G base stations. Indoor small base station mainly uses acoustic filters or dielectric mono-block filters, and point-to-point microwave backhaul system mainly uses waveguide filters. The evolutionary trend of filter technology is different for the different BTSs which are introduced in this paper. The special process in filter manufacture, namely, tuning is also discussed.