Advanced antenna systems for wireless power transfer, localization and train integrity

This thesis explores two distinct yet complementary research areas: Wireless Power Transfer (WPT) antenna systems and compact antenna solutions for Train Integrity Monitoring. The primary focus is on WPT, a transformative technology enabling the efficient wireless transmission of power. This work investigates two radiating architectures, Frequency Diverse Arrays (FDAs) and Time-Modulated Arrays (TMAs), that are highly reconfigurable in real time, offering enhanced power transfer performance with reduced costs. FDAs, traditionally used in radar due to their intrinsic scanning capabilities, are applied here for WPT for the first time. The radiation properties have been analysed and for the first time practical solutions have been proposed, trying to adapt the system for powering application. A novel scheme, Time-Controlled Frequency Diverse Arrays (TCFDAs), addresses FDA limitations by delivering precise power transmission to desired locations, outperforming conventional Phased Arrays (PAs) in medium- and high-power ranges, electing itself as one of the most interesting solution able to replace modern and expensive architectures with its multi-beam and highly reconfigurable radiation properties. TMAs, first explored in the 1960s, offer dynamic control over the radiation pattern using time-varying signals. While previous studies primarily focus on theoretical optimizations, this thesis addresses practical challenges in TMA design, proposing innovative 2D solutions with circular symmetry for highly directive, reconfigurable power transfer and localization applications. As a side activity, research on compact antenna systems for Train Integrity with the goal of providing a practical and efficient solution for co-locating multiple antennas without sacrificing performance is proposed. This work presents the design and validation of a compact wireless system with three co-located antennas operating in the 2.4 GHz band, intended for positioning purposes on secondary railway lines where the European Railway Traffic Management System (ERTMS) is unavailable. Using LoRa technology, the system enables low-power, long-range communication with acceptable latency.