Design of compact multiband microstrip BPF based on fractal open-ring configuration

Abstract EN

Multiband bandpass filters (BPFs) are one of the core elements in the multi-services wireless communication systems.

For this purpose, this paper presents a design of a compact multiband microstrip BPF design based on fractal open loop configuration.

The proposed filter structure is composed of an array of equal side length open-loop resonators; each with different fractal iteration level.

More specifically, the modified Minkowski fractal geometry has been adopted to be applied to the conventional open-loop rectangular resonator.

The resulting filter configuration has an array of different open-loop structures corresponding to various iteration levels.

The simulation of the presented filter is performed using the EM Sonnet software package environment.

The proposed filter is printed on a substrate of dielectric constant is 10.8 with thickness 1.27 mm.

A filter structure with three resonators having different fractal iteration levels offers a triple band frequency response around 3.05 GHz, 2.05 GHz, and 1.68 GHz.

Each of the three resonant bands is attributed by a distinct resonator according to the iteration levels.

Additional resonant bands can be realized using extra loops with higher iteration levels.