Open Stub Band-pass Filter Using Stepped Impedance Resonator for Size Reduction

摘要

This paper shows an open-stub narrow band-pass filter using a stepped-impedance-resonator (SIR). A SIR is adopted instead of transmission line to reduce the size of the BPF on the low dielectric substrate. The size of the conventional narrow BPF is reduced by more than 50% of its length of the transmission line within the inverter. The experimental results show that the insertion loss is 0.85 dB, return loss is 20.8 dB, and the fractional bandwidth is 10% at the center frequency of 5.8 GHz. The size of the filter is 12.7 × 18.56 mm~2.