Application of Koch island fractal on dumbbell-shaped defected ground structure low-pass filters

In this paper, fractal theory is applied to the defected ground structure (DGS), based on this application periodic dumbbell-shaped DGS low-pass filters with Koch island fractal structure were proposed. The comparison of Koch island structure filter and dumbbell-shaped DGS filter shows that the application of Koch island fractal on the dumbbell-shaped DGS filter can improve the passband performance, increase the frequency selectivity, and reduce the filter size.