Optimized fractional-order Butterworth filter design in complex F-plane

Abstract This paper introduces a new technique to optimally design the fractional-order Butterworth low-pass filter in complex F -plane. Design stability is assured by incorporating critical phase angle as an inequality constraint. The poles of proposed approximants reside on unit circle stable region improved accuracy suggested scheme compared recently published literature demonstrated. A mixed-integer genetic algorithm which considers parallel combinations resistors and capacitors for Valsa network used optimize frequency responses capacitor emulators part experimental verification using Sallen–Key topology. total harmonic distortion spurious-free dynamic range practical 1.5th-order Butterwoth are measured 0.13% 62.18 dBc, respectively; maximum mean absolute relative magnitude errors 0.03929 0.02051, respectively.