CMOS Ultra Wide-Band Impulse Radio Receiver Front-End

Abstract

As most radio communication is based on a narrow banded carrier tech­ nique, the technique this thesis is based on utilizes single impulse trans­missions and wide bandwidths. The technique is called Ultra WideBand Impulse Radio (UWB­IR) and is based on emission of single pulses and time domain processing. Through modulation and pulse shaping energy is contained within a specific band in the frequency spectrum. This implies that the technique is low power compared to narrow banded techniques wasting energy on a carrier wave conveying no info. Most radio receivers even UWB radio receivers is based on a template sampling scheme for signal detection and the utilization of a Digital Signal Processing (DSP) unit for signal processing.

In this thesis a novel low power front­end for impulse radio receivers suitable for implementation in standard Complementary Metal Oxide Silicon (CMOS) technology is presented. The novel architecture is exploring thresholding and continuous­-time delay lines avoiding high speed sampling clocks. The thresholding scheme is based on simple inverter structures, the topology consists of a Low Noise Amplifier (LNA), integrator, thresholding pulse shaper and pulse shape detector all in standard digital CMOS technology. The continuous time front-end utilizes no sampling clock and is designed to work with a RAKE receiver for low power ultra wideband applications. As reflections are destructive for most types of radio communication, the combined topology with the front­end and RAKE receiver utilizes reflections constructively as a gain in Signal to Noise Ratio (SNR).