New wideband microwave bandpass filter using single triangular patch resonator with low permittivity substrate

Fractal-shaped microwave passive circuits attract much attention recently. In this report, new planar bandpass filters with fractal patch defection by using equilateral triangular resonator and low permittivity substrate are presented to implement high performances of wide passband, transmission zeros, and low passband insertion losses. Using fractal defection acts as perturbation, single mode wideband bandpass filters are implemented, and filter performances are enhanced. Compared some reported dual-mode or multi-mode filters with the proposed ones, it shows the new filters have nicer performances even though operate at a single mode, simultaneously, posses compact and simple structures as well as miniaturization for having single patch resonator without coupling gaps. The advanced features of the proposed filters can be quite useful in wireless communication systems.