Design and Analysis of Diplexer using Various Types of Band Pass Filters

The main aim of this research is to design a diplexer for 5G communications as proposed by TRAI 3.4 GHz to 3.6 GHz. The device consists of Wilkinson power divider, Band Pass Filters (BPF) with 20 MHz bandwidth. Filters and power combiners are realized with center frequency of the band (3.5 GHz). Uplink frequency choosen is 3.41 to 3.49 GHz and downlink frequency choosen is 3.51–3.59 GHz. In this device the two band pass filtering structures (for both uplink and downlink) are joined by a three port junction. The diplexer design is done by dividing the structure in two parts, to make the design more efficient and feasible. Eventually the whole diplexer is optimized to fit the desired specifications. In this paper band pass filters are designed using coupled lines, short circuited stubs and also with capacitive coupled resonators. Performance of the diplexer is compared among all three filter configurations.