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We reexamine the characteristics of electrically short dipoles with nonlinear loads and, specifically, the early work of Motohisa Kanda. Although this topic has been examined in great detail in the past, some inconsistencies between numerical and analytical results are apparent, and these have not been previously addressed. We show that these inconsistencies were due to only periodic sampling of the analytic solution, and an insufficient number of iterations in the numerical solutions, and we give corrected results. Additionally, some of the more significant analytical results, which were once thought to be impractical due to their complexity, are numerically implemented. We also show that a simple approximation accurately describes the behavior of these electrically short dipoles over a wide range of frequency and amplitude.

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We describe methods for evaluating the performance of wireless devices such as wireless sensors in harsh radio environments. We describe how measurements of real-world propagation environments can be used to support the evaluation process. We then present representative measurement data from high-multipath environments where sensor networks are likely to be deployed: a fixed-infrastructure, process-control environment, here an oil refinery, and a heavy industrial environment, here an automotive assembly plant. The data are from an extensive set of studies carried out by the U.S. National Institute of Standards and Technology to provide open-literature data on radio-wave propagation over a wide frequency band in difficult radio-communication environments, including those with high loss and/or high multipath.