Design and analysis of improved fractional order Butterworth filters

This paper presents the optimal designs of fractional order low pass and high pass filters with the Butterworth approximation, which are obtained by using particle swarm optimization and suitable scaling. Further, the error analysis of the designed filters and the existing filters with the ideal ones is given to see the effectiveness of this optimization technique in the improvement of the designed filters over the existing filters in both, the passband and the stopband. In last, the improved fractional order low pass and high pass filters are used to design fractional order band pass filters.