Marco Dionigi

Electromagnetic Energy Harvesting and Wireless Power Transmission: A Unified Approach

In this paper, a rigorous procedure for the circuit-level analysis and design of entire systems, developed to provide power wirelessly, is presented. A unified theoretical approach is first introduced, based on a two-port-equivalent circuit representation, to describe the wireless power transfer link when the transmitter and the receiver are either in the near-field or in the far-field region reciprocally. This approach allows one to compute in a straightforward manner the system figure of merit, namely the power transfer efficiency. Specific guidelines for the two configurations are then intensively discussed together with the adopted software tools based on the combination of full-wave analysis and nonlinear harmonic balance techniques. Several practical examples based on this design procedure are presented, demonstrating predicted and experimental behavior of unconventional devices for both near-field and far-field power transfer usage.

Rigorous Network and Full-Wave Electromagnetic Modeling of Wireless Power Transfer Links

The proposed approach makes use of full-wave electromagnetic modeling of wireless power transfer links in order to derive the network characterization, e.g., in terms of scattering or impedance matrix. Once the latter is obtained, we show that network theory provides the appropriate matching impedances for achieving either maximum efficiency, maximum power on the load, or conjugate matching. The proposed approach also permits to derive closed-form matching networks and expressions for power and efficiency. An example of full-wave numerical electromagnetic modeling of a wireless power transfer link is presented. The selected example, which is similar to the experiment published by Kurs et al., shows the importance of selecting the appropriate source/load impedance for obtaining significative results.

A 5.6-GHz UWB Position Measurement System

This paper describes the design and realization of a 5.6-GHz ultrawide-bandwidth-based position measurement system. The system was entirely made using off-the-shelf components and achieves centimeter-level accuracy in an indoor environment. It is based on asynchronous modulated pulse round-trip time measurements. Both system level and realization details are described along with experimental results including estimates of measurement uncertainties.

Characterization and Modeling of an Experimental UWB Pulse-Based Distance Measurement System

This paper presents a distance-measuring system based on the accurate round-trip time-of-flight measurement of single ultrawideband pulses propagating between two transceiver devices. The architectures of two realized devices, which are referred to as the master and the slave, are described. The master device implements the time-interval measuring function by means of a time-to-digital converter (TDC) integrated circuit, whereas the slave acts as a pulse repeater. Both devices are designed for low-cost realization and low-power operations. Furthermore, two pulse-detection modules are described based on signal-threshold and energy detection, respectively. This paper also presents and discusses some experimental results that are obtained from the system prototype. Finally, some numerical simulation results, which provide an explanation for the nonidealities in the observed distance-measuring behavior of the system, are shown.

Microwave Circuits in Paper Substrates Exploiting Conductive Adhesive Tapes

In this work, a new technique to fabricate microwave circuits in paper substrates is proposed. This technique relies on a copper adhesive tape that is shaped by a photo-lithographic process and then transferred to the hosting substrate by means of a sacrificial layer. Microstrip lines in paper substrates have been electromagnetically characterized accounting also for the adhesive layers. Experimental results show an insertion loss better than 0.6 dB/cm at 10 GHz.

A fullwave CAD tool for waveguide components using a high speed direct optimizer

An extremely efficient optimization tool, where the fullwave mode matching simulator is driven by a quasi-Newton optimizer using the adjoint network method, has been developed for the CAD of a class of rectangular waveguide components. This includes filters, phase shifters, branch guide couplers, etc., with step in either the E- or H-plane. With respect to the conventional finite difference computation of the derivatives, a speedup factor of more than 10 times is easily achieved. >

A fullwave CAD tool of waveguide components using a high speed direct optimizer

Based on the adjoint network method (ANM) and on mode matching technique, an extremely efficient optimization tool has been developed for the CAD of a class of rectangular waveguide components. This includes filters, phase shifters, branch guide couplers, etc., with step in either the E- or H-plane. With respect to the conventional finite difference computation of the derivatives, a speedup factor of more than 10 times is easily achieved.<<ETX>>

A simple and low cost measurement system for the complex permittivity characterization of materials

A m A microwave planar resonanf sensor and the driving electronics for the measurement of fhe compler permitfivify in compact areas of the material under fesf (MUV is presented Compared to transmission or refecfion sensors, the adoprion of a scalar 2-porf measurement procedure reduces the cosf of fhe system and improves ifs robustness. The measuring sysfem requires on& fhe calculation of two paramefers, name& the resonant frequency and the 3dB bandwidth, thus achieving a subsfanfial reduction of cost and computafion rime. Such sensor can be adopted in moisfure measuremenf sysfems and ifs low cosf is such as fo allow is use even in a disposable monner.

A Low-Cost Ultra-Wideband Indoor Ranging System

This paper presents the development of a low-cost indoor ranging technique based on time-of-arrival (TOA) estimation, using short-pulse ultra-wideband (UWB) signals. The realized system includes two identical UWB transceiver devices, in which the receiver section is based on a tunnel diode detector and the pulse generation is performed by a common bipolar transistor driven in avalanche mode. An indirect measurement of the distance between the devices is obtained by measuring the frequency of the generated pulse train. A theoretical model of the system is described, and a statistical analysis is presented, including the closed-form evaluation of the Cramer-Rao lower bound (CRLB) on the distance estimation and showing the asymptotic statistical efficiency of the proposed estimators. Furthermore, the principle of operation of the realized system prototypes is described, along with some implementation issues. Finally, experimental results are shown and discussed.

An Indoor AC Magnetic Positioning System

This paper describes the design and realization of a magnetic indoor positioning system. The system is entirely realized using off-the-shelf components and is based on inductive coupling between resonating coils. Both system-level architecture and realization details are described along with experimental results. The realized system exhibits a maximum positioning error of <;10 cm in an indoor environment over a 3 × 3 m2 area. Extensive experiments in larger areas, in nonline-of-sight conditions, and in unfavorable geometric configurations, show submeter accuracy, thus validating the robustness of the system with respect to other existing solutions.