Comments

The accepted (peer-reviewed) version for self-archiving. A version of record is available at: https://doi.org/10.1007/978-3-030-50861-6_7

Cite this chapter as: Salam A., Raza U. (2020) Underground Phased Arrays and Beamforming Applications. In: Signals in the Soil. Springer, Cham.

Abstract

This chapter presents a framework for adaptive beamforming in underground communication. The wireless propagation is thoroughly analyzed to develop a model using the soil moisture as an input parameter to provide feedback mechanism while enhancing the system performance. The working of array element in the soil is analyzed. Moreover, the effect of soil texture and soil moisture on the resonant frequency and return loss is studied in detail. The wave refraction from the soil–air interface highly degrades the performance of the system. Furthermore, to beam steering is done to achieve high gain for lateral component improving the UG communication. The angle enhancing the lateral wave depends upon dielectric properties and usually ranges from 0∘ to 16∘. These dielectric properties change with the change in soil moisture and soil texture. It is shown from the experiments that optimal UG lateral angle is high at lower soil moisture readings and decreases with decrease in soil moisture. A planar structure of antenna array and different techniques for optimization are proposed for enhanced soil moisture adaptive beamforming. UG channel impulse response is studied from the beamforming aspect to identify the components of EM waves propagating through the soil. An optimum steering method for beamforming is presented which adapts to the changing values of soil moisture. Finally, the limitations of UG beamforming are presented along with the motivation to use it.

Keywords

Soil, Permittivity, Dielectric, Agriculture, Broadband antennas, Dipole antennas, Internet of Things, Moisture, Underground communication

Date of this Version

8-17-2020

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