This paper presents the design and analysis of a structural tapered finline for microwave application. The focusing frequency range are from 0.5 GHz to 6 GHz. Tapered finline or slotline has been used in Vivaldi antenna design to produce Ultra-wideband (UWB). In this paper, a parametric study and design of the vivadi structure has been undertaken with the aim of using them as elements to achieve wideband frequency. There are three main parameters studied in this paper which are of length of taper, exponential coefficient at curves of radiation and slotline width. Each parameter will be studied and analysed in order to see the changes. The design of tapered finline in power combiner is simulated using CST Microwave Studio Software. The simulation process is based on the input return loss at port 1 (S11), input return loss at port 2 (S22), insertion loss for port 1 (S21) and insertion loss for port 2 (S12). By studying the effects of the parameter on the design structure, it can ensure that the tapered finline structures are able to provide wide-band at certain frequency.