CMOS implementation of ultra-wideband systems

Ultra-Wideband systems is the collective term for wireless devices with a large spectral footprint and a low transmission power. The extreme low power spectral density of the UWB system forms a vast difference with classic communication systems that employ a large power within a small frequency band. Implementation approaches of Ultra-Wideband enclose classical carrier-based OFDM systems and pulse-based systems, each with their play trumps and disadvantages. Depending on the final application, cost, power or bandwidth can be the key target. Deep-submicron technologies allow to extend the limiting boundaries of analog building blocks but also introduce new challenges. Furthermore, new problems with respect to analog design deserve our attention: The high bandwidth of the signals involved in wideband systems obliges to migrate to a broadband receiver chain: LNA's (Low Noise Amplifier), mixers and ADC's with a wideband in- and output have to be designed, while commonly used techniques such as inductive peaking in the power amplifier cannot be used any more. Both advantages and disadvantages of OFDM and pulse-based transceiver architectures will be compared, together with simulation data, in order to give an overview of important design aspects of an Ultra-Wideband application.status: publishe