Comparison of Feedback Influence on Ring Oscillator Performance for IR-UWB Pulse Generator in 0.13 μm and 0.18 μm CMOS Technologies

Part 20: Electronics: RF ApplicationsInternational audienceA CMOS three-stage ring oscillator is examined in UMC 0.13 μm and 0.18 μm technologies. The influence of PMOS transistor and resistor, as inverter feedbacks, on the ring oscillator frequency and the peak-to-peak amplitude is investigated in both technologies. Furthermore, as the ring oscillator usually drives a buffer in pulse generator/transmitter chain, dependence of its Figures of Merit on the buffer feedback is presented in the paper. Simulation results showed that the ring oscillator frequency is strongly dependent on the inverter feedback. The presented techniques can be used to increase (resistive feedback) and control (PMOS transistor feedback) the ring oscillator frequency. As the ring oscillator is a part of an IR-UWB (Impulse Radio Ultra Wide Band) pulse generator, its oscillating frequency determines the spectrum central frequency and has significant effect on spectrum fitting within UWB FCC mask

A CMOS Energy-Detector for Impulse-Radio UWB Noncoherent Receivers

Abstract-This paper presents the design of an energy detector for ultra-wideband impulse-based applications. It comprises a squarer using a passive mixer and an integrate-and-dump circuit on a single stage. A current-reuse topology was chosen to reduce the overall power consumption. The proposed energy detector targets low data-rate communications for noncoherent receivers, using on-off keying modulations. The circuit has been designed in a CMOS 180-nm process with 1.8-V power supply. The simulation results show a total power dissipation of 287-μW for a 1-Mbps data-rate using an indoor channel model. Index Terms-impulse-radio ultra-wideband, analog squarer, integrate-and-dump, noncoherent receiver