An Insight into Creeping Electromagnetic Waves around the Human Body

The electromagnetic wave propagation around human body torso is modelled by considering elementary electric and magnetic dipoles over an infinite muscle-equivalent cylinder. The poles in the spectral domain Green’s function with smallest imaginary part are found to correspond to creeping wave propagation coefficients which predict the general trend in propagation around human body. In addition, it was found that axial magnetic field component is crucial for communication via creeping waves since it generates modes with smaller field decay compared to axial electric field. The developed model may thus serve as a practical guideline in design of on-body wearable antennas. The theoretical considerations are verified with simulations and measurements on the prototype of PIFA antenna placed on the human body

An Adiabatic Coaxial Line for Microcalorimeter Power Measurements in Wireless Communication for Smart Grid

This paper presents the extended results and prototype of the adiabatic copper conductor constructed with two interruption points in the external conductor layer, for use as a microcalorimeter power standard in wireless communication for a smart grid frequency range. Gaps are intended to drive down the thermal transfer from the outer environment into microcalorimeter and to reduce measurement inaccuracies in the microcalorimeter. The proposed design method is based on the combination of thermal and electromagnetic finite-element method simulations by which the desired line performance has been tailored. A prototype of the proposed adiabatic line has been manufactured and measurements on the prototype are presented along with the design procedure. Measured results are in line with the ones predicted by numerical calculations

Line parameters estimation in presence of uncalibrated instrument transformers

This paper presents a method to estimate parameters of a 3-phase line segment using PMU data. The novelty of this method is that it is capable of giving accurate estimates even in the presence of non-calibrated instrument transformers at both ends of the line whose ratio and phase correction coefficients are unknown. To do so, this method adds extra parameters in the regression model. These added parameters account for the errors present in the non-calibrated instrument transformers. In case the instrument transformers are calibrated at one end of the line, then the correction coefficients at the other end could also be estimated. The presented method does not require reversal of current flow direction in the line as a necessary condition. Results from simulated and laboratory experiments are presented to show the efficacy of the method. A discussion about analyzing the obtained results is also presented