Design of Fractional-Order Chebyshev Filter with FOE Based on R-C-NR Structure

Inhalt:
The design of the Chebyshev fractionalorder frequency filter with FOE (Fractional-Order Element) is presented in this paper. The FOE is designed based on a distributed R-C-NR (Resistive-Capacitive- Resistive with N-times resistance) layer structure and provides the desired phase value with minimum error over a wide frequency band. The program created in MATLAB environment using genetic algorithms was used to find the optimal parameters and optimize the structure emulating FOE properties according to the specified requirements. The presented circuit is designed with the order 2.82 and provides low-pass and high-pass filtering functions. The possibility to change the value of cut-off frequency in range from 50 to 200 kHz and pass-band ripple in range from 3 to 9 dB by changing the value of the transconductances is also presented. Features of the designed filter are verified by simulations in OrCAD PSpice for selected values of cut-off frequency and pass-band ripple.