CNTFET-Based Single-Ended Fractional Order Colpitts Oscillator: Design, Simulation and Comparative Analysis

Abstract

In this paper, we design and simulate a Single-Ended Colpitts Oscillator (CO) in integer and fractional order domains. The oscillators are realized in 32[Formula: see text]nm node conventional MOSFET and carbon nanotube field effect transistor (CNTFET) technologies. Therefore, four COs have been designed, simulated and rigorously compared. These include integer order conventional MOSFET-based CO, fractional order MOSFET-based CO, CNTFET-based integer order CO and CNTFET-based fractional order CO, all based on 32-nm technology nodes. The fractional order approach has been used as it results in better control over the phase and frequency of the oscillator. Herein, fractional order capacitors of various orders, used in realizing the fractional order COs, are realized and their frequency responses are studied. This is being done to ensure whether the designed pseudo-capacitances have fractional behavior or not in the desired frequency and phase spectrum. It has been observed that the variation of fractional order [Formula: see text] from 0.4 to 0.81 has resulted in a slight reduction of oscillation frequency from 1.68[Formula: see text]GHz ([Formula: see text]) to 1.351[Formula: see text]GHz ([Formula: see text]) keeping the pseudo-capacitance same at 0.3[Formula: see text]nF in MOS-based topology. Since the fractional order realization increases the circuit complexity and power consumption, therefore, CNTFET-based integer order as well as fractional order COs have been designed. The CNTFET-based fractional order CO retains the advantages of the fractional order domain as well as the power efficiency of CNTFETs. Further, it has been observed that integrating fractional-order capacitor (FOC) with the CNTFET CO results in a much larger constant phase zone (CPZ), an important performance measuring parameter. A rigorous comparative analysis of the four COs designed in this work has been performed.