Novel dual-mode microstrip bandpass filters using fractal-shaped triangular patch resonators

In this paper, two types of bandpass filters using fractal-shaped triangular resonators are proposed, and their filter performances are simulated and optimized. By using etched fractal-shaped defected structures in the triangular patch resonators, both of the filters have compact sizes, high selectivity and simple structures. The effects of parameters variation for the fractal-shaped structures are also studied. Measured results of the filter using three fractal-shaped structures are in good agreement with the simulated ones.