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Recently, the concept of a nanonetwork has attracted large attention of researchers as it potentially offers low-cost solutions for a wide spectrum of current applications and enables numerous emerging ones. At present, however, all the sensor networks consist of a relatively small number of macroscale devices with their positions carefully pre-determined. The typical nanonetwork, on the contrary, can be envisioned as a swarm of nanomachines that are distributed in a random manner, which also can reach covered places, accomplish sensing directly inside a phenomenon or equip an application with enhanced control capabilities. To operate and monitor within a macroscale application area, information sharing between nanonetwork entities is required (likewise data transfer among human cells). Electromagnetic waves at microwave frequencies can potentially enable wireless communication between nanomachines even in vicious and hazardous environments. However, the paradigms of traditional microwave communication must undergo a substantial revision before being applied to nanotechnology: due to space restrictions, nanomachines have very strong power limitations and should be capable to operate on an extremely tight energy budget. This places a very strong restriction on the communication link power budget. Moreover, networking-level techniques capable of describing a connectivity and signal propagation in the 'topology-less' nanonetwork are currently missing. These two open issues served as primary motivating factors for this doctoral dissertation, which broadly focuses on the feasibility and development of electromagnetic-based communications for nanonetworks., Microelectronics, Electrical Engineering, Mathematics and Computer Science

A semi-analytical model for current estimation on a thin complex-impedance-based monopole, mounted on a perfectly conducting sphere and fed in an arbitrary point of its aperture is proposed. By applying the current thus obtained, the electromagnetic fields excited by the antenna system are determined. The influence of an impedance coating and a feeding point position on the current distribution and radiation pattern is thoroughly investigated.

The power budget of a wireless link between two electrically small sensor nodes located close to an interface between two media is studied. The model includes both the propagation channel losses and input impedance of the radio frequency antennas. It is shown that a highly inductive half-space significantly enhances the received power due to the contribution of the surface wave while not resulting in considerable mismatch losses between the antennas and electronics. Hence, such a half-space improves the link gain, which may compensate the limited energy available for transmission from electrically and physically small nodes., Microelectronics, Electrical Engineering, Mathematics and Computer Science

To effectively localise a source node in a dense wireless tiny-sensor network with an arbitrary 2D/3D node distribution, a novel approach suitable to describe the hop progress of source-to-sink path in such a system is proposed. In this approach, the network topology is described as a regular lattice and relates the statistical parameters of the hop count in the source-to-sink propagation path to the fractal properties of a percolating cluster. Based on this approach, a mathematical model is developed to estimate the probability P(r,t) of successful reception of the message by a sink node spaced at distance r from a source in a given time t. The accuracy analysis of the positioning method demonstrates its high performance for the very broad spectrum of values of the occupation probability pocc., Microelectronics, Electrical Engineering, Mathematics and Computer Science