Application of slope uniform theory of diffraction with convex hull model onto a wireless sensor network powered by wireless energy transfer

In order to perform complex tasks or multiple functions for sensors, they must build a network and be managed from a central point. In order to build this structure, a module called Sensor Node (SN) has been developed by adding processor, energy unit and antenna to the sensor. When multiple SNs come together, Wireless Sensor Networks (WSN) are formed. The most important work area in the WSNs are energy efficiency and providing energy to the SNs permanently. In this thesis, the MAC protocols developed to provide energy efficiency in SNs were mentioned. Providing energy from an external source to SN subject was examined in details. Especially, the advantages/disadvanteges of energy harvesting from the environment and transfer energy from a fixed source to WSNs were compared. As a result of researches, we were focused on RF energy transfer. During energy transfer, losses occur due to the distance and disrupting obstacles between antennas, hence energy transfer was inefficient. In order to calculate energy transfer between transmitter and receiver, electromagnetic wave propagation models were examined. Geometrical Optics (GO), Physical Optics (PO), Geometrical Theory of Diffraction (GTD), Physical Theory of Diffraction (PTD), Uniform Theory of Diffraction (UTD) and Slope Diffraction (S-UTD) models were mentioned. Afterwards, Slope Uniform Theory of Diffraction with Convex Hull (S-UTD-CH) was analyzed in detail. As a result of examinations, it was decided to use S-UTD-CH due to the advantage of calculation time. The elimination of ineffective buildings from the calculations is one of the most important features of S-UTD-CH. To provide this a new algorithm was generated and a MATLAB code was developed to calculate Fresnel Zone and Convex Hull. Calculations were made for different scenerios with the MATLAB code developed. Fresnel zone radius is decreased with increasing of the frequency. To verify the outputs obtained in the developed MATLAB code, the high frequency calculation program FEKO was used. Similar results were obtained in both programs. Finally, test scenerios have been generated for recievers at different location and heights with the transmitter used as an energy station positioned at different points. The tests are performed at different frequencies with UTD, S-UTD and S-UTD-CH models. The results of these models are compared. In WSNs the most suitable point for locating the transmitter has been identified to ensure the highest energy to receiving SNs.