Design of miniaturized high selectivity folded substrate integrated waveguide band pass filter with Koch fractal

Abstract

ABSTRACTThis paper proposes the design of a novel double folded substrate integrated waveguide (FSIW) band pass filter (BPF) based on Koch space-filling curve (SFC). The folded SIW filter is incorporated with first and second iteration levels of Koch curve on central conducting layer. A prototype of second iteration Koch fractal FSIW BPF has been fabricated using substrate having dielectric constant 2.55 and thickness 0.508 mm for each layer and then tested. The fabricated second order filter has merits of compact size (0.204 λ02), high roll off rate (82.2 dB/GHz) and low insertion loss (<0.85 dB) in the X band.