Research Activities

A NOVEL INTEGRATED UWB–UHF ANTENNA FOR LOCALIZATION AND ENERGY HARVESTING

A novel antenna combining both UWB and UHF bands. Proposed for next-generation passive RFID tags, performing communication and localization through UWB technology and efficient energy harvesting in the UHF band, is also designed to keep compatibility with previous tags generations. The UWB communication is deployed by means of an Archimedean spiral topology, while energy harvesting at UHF is obtained by suitably extending the spiral outer arms, thus realizing a meandered dipole, without affecting the UWB behavior. This solution allows a direct connection to future integrated UWB-UHF chips, to standard RFID chips, or to a diplexer for suitably combining the UWB and the UHF functionalities.

A UHF NEAR-FIELD LINK FOR PASSIVE SENSING IN INDUSTRIAL WPT SYSTEMS

An innovative nonconventional exploitation of a self-resonant capacitive near-field link at UHF, for data communication, to be combined in a compact wireless power transfer (WPT) system has been investigated. At UHF, an increased channel transfer efficiency is made possible by exploiting two faced auto-resonant structures, such as split-ring resonators, one at each far-end side of the link. This network is then used in a passive sensing system, based on a smart exploitation of the dc-power dc-load relationship of a standard RF identification (RFID) rectifier, to convert the data of a remote sensor, representing the system variable load. The entire sensing system is first optimized by means of nonlinear circuit and electromagnetic simulations.

SEAMLESS EXPLOITATION OF CELL-PHONE ANTENNAS FOR NEAR-FIELD WPT

This is a solution for portable devices to exploit their existing communication antennas (i.e. 900/1800 MHz ) for bi-directional near-field wireless re-charging (433MHz), without compromising their far-field properties. Definition of the equivalence between electromagnetic structures and lumped elements circuit models has been defined.
Prototype has been realized and performances are investigated at different distances when facing two identical dual-band printed monopole. A proof-of-concept prototype has been realized and characterized.

LOAD- AND POSITION INDEPENDENT MOVING WPT SYSTEM

A complete (dc-to-dc) inductive wireless power transfer (WPT) system for industrial moving applications has been investigated. The system operates at 6.78 MHz and delivers up to 150 W to a load moving along a linear path, providing a quasi-constant dc output voltage. Through optimization of both transmitting and receiving coils, a constant coupling factor has been obtained in an inductive link. The work in this paper is foreseen as a design solution for a high-efficient, maintenance-free, and reliable WPT system for powering sliders and mass movers in industrial automation plants.

ARTIFICIAL NEURAL NETWORK DESIGN OF A MILLIMETRE-WAVE SLOTTED PATCH MULTI-ANTENNA CONFIGURATION FOR 5G SCENARIOS

This study addresses the modelling of a dual band (28 and 38 GHz), circularly polarised slotted-patch-antenna for highly demanded millimetre wave multi-input multi-output (MIMO)-systems in fifth generation (5G) networks. A computer-aided-design model is derived by means of an artificial neural network (ANN) which allows obtaining the physical dimensions of a single-fed antenna, satisfying both near- and far-field goals, without resorting to time-consuming electromagnetic simulation and allowing, for the first time, to carry out optimisations of strategic importance for future 5G non-linear-radiating-systems, especially operating at millimetre wave, directly addressing their far-field behaviour. The model performance is validated by some examples and measurement results.

TIME-MODULATION OF LINEAR ARRAYS FO REAL-TIME RECONFIGURABLE WIRELESS POWER TRANSMISSION

A smart wireless power transmission method, based on a two-step procedure, exploiting real-time beaming of time-modulated arrays has been investigated. The sideband radiation phenomenon, which is usually a drawback of these radiating systems, is favorably used for intentional wireless power transfer (WPT): in a first step to precisely localize the tag to be powered and in the second one to perform directive WPT. Experiment of the first step is carried out in a real indoor environment at 2.45 GHz: a TI MSP430 drives a Schottky-diode-based network to provide proper modulated RF excitations of the array elements. Measurements show that the system is able to select tags to be energized randomly distributed in a 100 -scanning range.