A fractal-based dual-mode microstrip bandstop filter for wireless applications

Bandstop filters (BSFs) are highly required in modern wireless communication and electromagnetic compatibility related applications. In this paper, a fractal based dual-mode microstrip BSF has been proposed as a compact resonator structure with high selectivity. Filter miniaturization results from the application of Minkowski fractal geometry on the conventional triangle dual-mode resonator. Performance evaluation of the proposed filter design has been performed using the commercially available EM simulator; Sonnet. Parametric study reveals that the application of Minkowski fractal geometry results in BSFs offering both a compact size and high selectivity stopband responses. The results show that the proposed BSF over performs those reported in the literature in both the size reduction and the realized selectivity.