volume | PIER Journals

Abstract

Antennas operating in the close vicinity of obstacles or scatterers behave much different from isolated antennas radiating in free space. To assess such interactions in which a large number of parameters are involved (pertaining to the geometry, possible movement effects, and materials), stochastic models are often conceived and adopted so as to cope with innate uncertainties and to overcome the need for time-consuming parametric investigations. In this paper, an analytical stochastic approach is presented for the archetypical problems of the vertical, horizontal, and arbitrarily oriented dipole above a semi-infinite ground (either perfectly conducting or dielectric). The analysis focuses on how the input impedance of the dipole is affected by the existence of the ground plane when the distance or the angle between them varies in accordance with some certain probability distributions. Approximate closed-form expressions are obtained for the probability distributions of the input resistance and reactance separately, which can directly yield the respective moments and variances (and potentially other quantitative measures) and are useful for characterizing the probabilistic behavior of the dipole and its interaction with the ground. Representative numerical results are presented aiming at the validation of the proposed model and the investigation of the probabilistic behavior of the impedance change. Finally, a few concluding remarks are outlined, and possible extensions to real-world problems are discussed.

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Dr. Aikaterini Mangou

Dr. George P. Veropoulos

Dr. Constantinos Vlachos

Dr. Panagiotis Papakanellos