New Dual Band Dual-Mode Microstrip Patch Bandpass Filter Designs Based on Sierpinski Fractal Geometry

Abstract

Dual band dual mode chebychev microstrip bandpass filter designs are introduced for first time in this paper. The proposed filter designs are based on the use of dual mode square slotted patch microstrip resonator. These filter structures are fractally generated using Sierpinski fractal curve geometry applied to the conventional square microstrip patch from 1st to 2nd iteration levels where the first band designed at fundamental frequencies (5.475, 5.45 and 5.4) GHz for each iteration while the second band(8.925, 9.15, 9.05) GHz for each iteration. These filters have been designed using a substrate with a dielectric constant of 10.8 and thickness of 1.27mm. The performance of filter structures, based on resonators has been evaluated using a full-wave based electromagnetic simulator Sonnet software package. Performance simulation results show that these filter structures are compact in addition to good frequency responses and narrow bands gained.