This article describes the modeling of ultra-wideband wireless propagation channels, especailly for the simulation of personal area networks. The IEEE 802.15.3a standards task group has established a standard channel model to be used for the evaluation of PAN physical layer proposals. We discuss the standard model, the measurements that form its basis, and the possibilities for future improvements. The article points out the important differences between UWB channels and narrowband wireless channels, especially with respect to fading statistics and time of arrival of multipath components. The impacts of the different propagation conditions on system design, like Rake receiver performance, are elaborated. IEEE Wireless CommunicationsThis work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved.

No abstract

This paper provides a tutorial overview of ultrawideband (UWB

No abstract

and inverted, compared to the radiating-basis triangular element, is introduced on this antenna (Fig. 5). The goal here is to combine the matching frequencies of the two created antennas (one with h 1 ϭ 7.5 mm, and the other h 2 ϭ 15 mm) and thus to widen the resultant bandwidth of the structure.This results in a VSWR of about 1.5 (Fig. 6) and a much better adaptation from 3 to 7 GHz (Fig. 7). By comparing these results with those obtained experimentally, a widening of the bandwidth after 7 GHz (which was not observed in the simulation, can be noted. This variation is certainly due to the phenomenon of loss adaptation related to the poor performances of epoxy at high frequencies. The fact that this antenna is fed by a broader CPW line than that of the preceding one (the wave only propagates in the substrate under the feeding line) may explain why this phenomenon was not perceived in the first antenna.The addition of the slot does not disturb the radiation pattern, in comparison with the first structure, while the efficiency is better and fluctuates around 80% over the entire bandwidth (Fig. 8). CONCLUSIONTwo new omnidirectional antennas for short-range UWB communications have been presented; the first one amply covers the WPAN standard, and the other one presents a very good adaptation and good radiation efficiency on a very broad frequency band. Both antennas are approximately the same size as a standard business card, have low manufacturing cost, and are matched to 50⍀. Optimizations of radiation pattern and tests on better quality substrate should increase the high-frequency performances of these two antennas. Figure 7 Real and imaginary parts of the input impedance PILOT: A FAST ALGORITHM FOR ENHANCED 3D PARASITIC CAPACITANCE EXTRACTION EFFICIENCY