Wireless personal area networks applications may benefit from the use of ultra-wideband (UWB) technology. 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 new validated with measurements using different types of antennas. The measurements have been performed in the time domain by exciting the antenna with very short pulse of 35 ps width covering a large frequency band. The proposed model, which includes frequency , antenna size and orientation as parameters, shows a good agreement with the simulations and the measurements.@en

Ultra Wide Band (UWB) technnology is prome to be used in wireless personal area networks (WPAN) applications. 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 modesl may not be satisfied. Under near field conditions, variations in the link budget and pulse shape with respect to the far fiedl can be observed. In this work, near field WPAN measurements have been carried out with three different biconical antennas in order to analyze the link budget. A new link budget model is proposed and compared with the measurements. Results can be used in the design and coverage analysis of UWB communication systems for WPAN applications.@en

This paper presents the results of Ultra Wide Band (UWB) channel measurements for Wireless Personal Area Networks (WPAN). A time domain measurement setup has been developed covering the frequency band from 2.1 GHz. Relevant scenarios for WPAN applications have been proposed and measurements have been conducted in an office at very short distances including both LOS and NLOS cases. Additional NLOS measurements with a human body obstructing the direct path have also been performed to determine the effects of the body on teh UWB-WPAN channel characteristics. In addition to this, the near field effect between transmit and receive antenna has been examined and channel parameters such as root-mean-square (RMS) delay spread, Ricean K-factor and path-loss exponent are obtained. These results can be used for analysis and design of UWB systems for WPAN applications.@en