Three Fractional-Order-Capacitors-Based Oscillators with Controllable Phase and Frequency ¤ Lobna A. Said Nanoelectronics Integrated Systems Center (NISC), Nile University, Cairo, Egypt l.a.said@ieee.org Ahmed G. Radwan † Nanoelectronics Integrated Systems Center (NISC), Nile University, Cairo, Egypt Engineering Mathematics and Physics Department, Cairo University, Cairo, Egypt agradwan@ieee.org Ahmed H. Madian Nanoelectronics Integrated Systems Center (NISC), Nile University, Cairo, Egypt Radiation Engineering Department National Centre for Radiation Research and Technology, Egyptian Atomic Energy Authority, Cairo, Egypt ah _ madian@hotmail.com Ahmed M. Soliman Electronics and Electrical Communications Engineering Department, Cairo University, Cairo, Egypt asoliman@ieee.org Received 2 September 2016 Accepted 9 February 2017 Published 5 April 2017 This paper presents a generalization of six well-known quadrature third-order oscillators into the fractional-order domain. The generalization process involves replacement of three integer- order capacitors with fractional-order ones. The employment of fractional-order capacitors allows a complete tunability of oscillator frequency and phase. The presented oscillators are implemented with three active building blocks which are op-amp, current feedback operational *This paper was recommended by Regional Editor Piero Malcovati. † Corresponding author. Journal of Circuits, Systems, and Computers Vol. 26, No. 10 (2017) 1750160 (22 pages) # . c World Scienti¯c Publishing Company DOI: 10.1142/S0218126617501602 1750160-1