Novel Soil Impact Prediction Model on Bandwidth

International audienceThe antenna's bandwidth strongly depends on its physical characteristics and the surrounding environment. However, permanently embedding devices in the soil causes inherent instability in the propagation medium due to spatial and temporal variations in dielectric permittivity. This study introduces an innovative multivariable approach that effectively captures dataset patterns, enabling accurate prediction of frequency range variations, at around 70%. This technique relies on the multiple linear analysis method and considers soil parameter values. Furthermore, our research findings demonstrate that among the four key variables, volumetric moisture exhibits a pronounced influence on the operating band, with a notable correlation coefficient of 0.72, whereas temperature and bulk density show scores of -0.381 and 0.08, respectively. On the other hand, the effect of specific density appears to have minimal significance. The obtained results successfully achieve the set objectives of this study by providing critical information for designers to address the challenges that transmitters may encounter in such scenarios

Moisture vulnerability of antenna operation in UHF band

International audienceBehavior of the propagation medium in reaction with electromagnetic fields is described by its dielectric permittivity; this electric property is a function of the physical characteristics of the medium and those of the propagating wave. Among the parameters, which considerably affect the dielectric permittivity of a medium, its water content. In fact, when the snow wetness varies from 0 to 50% in the melting layer, real part of the mixture permittivity varies from 1.47 to 5.86. Similarly, when soil moisture varies from 0 to 40% real and imaginary parts of effective permittivity of soil, air and water mixture vary from 4.13 to 24.85 and from 0 to 3.44 respectively. This dynamism in the permittivity as a function of the humidity is able to alter the efficiency of the antenna within the application. In this paper, we propose a study to analyze the impact of wetness on the performance of a dipole antenna with central frequency of 900 MHz. The study was carried out by simulating the behavior of the dipole antenna model in Finite Element Method (FEM) full wave simulator with different values of the water content of two propagation mediums: melting layer and soil. Simulation results concerning the resonant frequency, bandwidth, directivity are presented through paragraphs of the paper