Link Budget Analysis and Modeling of Short-Range UWB Channels

Ultrawideband (UWB) technology is an attractive alternative for short-range applications, e.g., wireless personal area networks. In these applications, transmit and receive antennas are very close to each other and the far-field condition assumed in most of the link budget models may not be satisfied. Under near-field conditions, variations in the link budget and pulse shape compared to the far-field can be observed. In this work, a novel line-of-sight UWB link budget model for very short distances is proposed and validated with measurements using different types of antennas. The proposed model, which takes into account all main near-field effects (i.e., phase error, antenna mismatch and reradiation between antennas) and includes frequency, antenna size and orientation as parameters, shows a good agreement with the simulations and the measurements. This model has also been applied to dispersive antennas (e.g., notch-antennas), and can be used in the design and analysis of short-range UWB communication systems.