Design and Analysis of Triple Band BPF Using Stub added Ring Resonator

In this paper, a compact Tri-band band pass filter (BPF) was designed with two ring resonators, two semicircle stubs and four stubs loaded resonators (SLRs). The two semi-circle stubs used in the internal region of the conventional double mode ring resonator can support dual band operations. Moreover, a higher third pass band is found when the SLRs are introduced in the dual-band BPF. Using this proposed structure, a Tri-band Band pass filter (BPF) was modeled and simulated by using the Ansoft HFSS 15 software. The simulation result shows that the compact Tri-band BPF operates at 3.22 GHz, 6.34 GHz and 8.90 GHz with return loss of -22.29 dB, -18.24 dB and -11.2816 dB, and fractional bandwidth of 2.77%, 1.89% and 0.79% respectively.