Approximation of the fractional-order laplacian S? as a weighted sum of first-order high-pass filters


A new approximation method of the fractional-order Laplacian operator s? is introduced. The approximation is based on a weighted sum of first-order filter sections and its analytical proof is given. The optimal high-pass filter section parameters that cover six frequency decades are obtained using the flower pollination algorithm while the effect of the number of filter sections on the accuracy of the approximation is investigated. Approximations of fractional-order capacitors of orders ? =0.5 and ? =0.7 synthesized in Foster-II form are given as a validating example. Further, an active emulator of a fractional-order differentiator function based on this technique is also proposed and experimentally validated. © 2018 IEEE.


AbdelAty A.M., Elwakil A.S., Radwan A.G., Psychalinos C., Maundy B.J.


fractional-order capacitors; Fractional-order circuits; fractional-order integration/differentiation

Document Type



IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 65, Art. No. 8301600, PP. 1114 to 1118, Doi: 10.1109/TCSII.2018.2808949

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