4.2.1 The equivalent lumped circuit model analysis of the proposed design

Figure 22 shows the equivalent lumped circuit model of the proposed UWB BPF that is shown in Figure 21. The equivalent lumped circuit model results are obtained using circuit model tool of the Advanced Design System (ADS) 2017. The lumped element values are manually optimized by changing each element value, so that it can have good agreement with the simulated results obtained from the full wave simulator.

The whole equivalent circuit of the proposed filter can be divided into the following subsections: DGS part at input and output ports, interdigital coupled lines and stepped impedance open stub. As shown in the lumped element model (Figure 22), Rd1, Cd1, Ld1, Rd2, Cd2, and Ld2 represent the equivalent resistance,

Figure 22. Equivalent lumped circuit model of the proposed UWB BPF shown in Figure 21 [50].
