Fractional Order Voltage Controlled Oscillator with Injected Orthogonal Signals at Base: Design and Simulation

This work focuses on the design and simulation of a differential Colpitts voltage controlled oscillator (VCO) in integer and fractional domains. The proposed VCO employs n and p-type metal oxide semiconductor field effect transistor (MOSFET) coupling along with injected orthogonal signals at base. The designing uses 32nm MOS technology node at an operating voltage of 1 volt. Both integer order capacitors and the fractional order based pseudo-capacitors have been used for designing the VCOs. The comparative analysis of the key performance measuring parameters has been done using HSPICE. It has been observed that the fractional order circuitry provides much greater phase and frequency control due to an additional parameter, fractional order α, which is not possible in an integer order circuitry. The simulations have shown that increasing α decreases the oscillation frequency of the VCO. At α=0.4, the oscillation frequency is 13.33 GHz and it decreases to 12,6 GHz for α=0.81. However, the fractional order VCO circuit results in more power consumption than the integer order, which is its biggest limitation.