Wideband microstrip bandpass filter using single patch resonator

Fractal-shaped microwave passive circuits attract much attention recently, but dominantly applied in antennas. In this report, new fractal bandpass filters using equilateral triangular patch resonator are presented to implement high performances of multi-transmission zeros, wide passband and stopband, and low passband insertion loss as well as miniaturization. Using fractal defection in patch, multi higher order modes are driven for coupling a much wider passband, and parasitical harmonics are effectively suppressed as well. Compared with some literatures, sizes of the new filters reduced and performances are greatly enhanced. The proposed filters have compact and simple structures, small sizes, high selectivity and so on, and all these features are the requirement of wireless communication systems.