Wideband bandstop filter using an SIR based interdigital capacitor

Abstract

AbstractIn this article, a microstrip wideband bandstop filter (W‐BSF) with a stepped impedance resonator (SIR)‐based interdigital capacitor (IDC) is proposed. By using an SIR‐based symmetric IDC, a wide rejection of bandwidth of 4.27 GHz at the center frequency of 5.85 GHz can be achieved. The insertion loss (S21) and return loss (S11) were 17.89 dB and 0.22 dB at 5.85 GHz, respectively, in the measurement results, which also verified that the bandwidth can be widely tuned by increasing the length, d from the main transmission line to the SIR‐based symmetric IDC section. As a result, we achieved practically applicable simulated and measured S‐parameter responses. The overall dimension of the optimized W‐BSF was (13.80 × 10.98) mm2.