M. Maini

An integrated RF energy harvester for UHF wireless powering applications

A RF energy harvester comprised of an integrated differential RF-DC converter and a differential PCB custom antenna is presented for wireless powering applications in the UHF band. The RF-DC converter, based on a reconfigurable voltage rectifier directly connected to a matched PCB antenna, is designed for high efficiency and sensitivity. Prototypes of the RF-DC converter realized in CMOS 130nm technology show a -16dBm sensitivity and a 60% peak efficiency. The RF-DC converters operate within the -16dBm÷0dBm input power range with an efficiency which remains above the 40% for more than 10dB. The RF energy harvester operates on the 840MHz-975MHz band thanks to the ad-hoc designed wide-band differential antenna.

Numerical Modeling of S-Band EDFA Based on Distributed Fiber Loss

A numerical model for the analysis and design of S-band erbium-doped fiber amplifiers has been developed. The model is able to accurately predict the amplifier performances by taking into account the amplified spontaneous emission suppression due to the bending, as well as leakage losses of the fiber used as active medium. The model has been validated by comparing numerical and experimental data of bending loss, amplifier gain, and noise figure of an S-band optical amplifier based on a depressed-cladding erbium-doped fiber. A good agreement has been verified by varying fiber bending radius, input signal power, and wavelength. The model has been then applied to the optimization of the amplifier performances for wavelength-division multiplexer applications. The numerical results show that 20-25 dB gain can be achieved over a 25-30 nm range centered in a different part of the S-band from 1460 to 1525 nm, just by changing the bending radius and the length of a depressed-cladding fiber.

Broadband printed antenna for radiofrequency energy harvesting

In this work a broadband UHF antenna with high inductive input impedance for radiofrequency energy harvesting is presented. It consists of a small feeding loop and a biconical radiating dipole. A prototype has been fabricated on a FR4 substrate and tested. Experimental results show a -3dB power transmission bandwidth of about 135MHz (840MHz-975MHz).

Electromagnetic analysis of PD detection in GIS systems

In this work the radiation of the electromagnetic field due to partial discharges throughout the insulation spacer of Gas Insulated Switchgears is investigated. Radiation can be described in terms of resonant modes of the slot between the metallic bolts. Moreover other resonant modes due to the spacer flanges are observed and investigated for the first time.

Integrated RF-DC converter and PCB antenna for UHF wireless powering applications

In this work, a broadband differential RF-DC CMOS converter realized in CMOS 130 nm technology with a customized PCB antenna with inductive coupling feeding for RF energy scavenging is presented. Experimental results show that output DC voltage higher than 1V from 800MHz to 970MHz can be obtained with a load of 1kΩ.

Single-ended broadband antenna for radiofrequency energy harvesting

A single-ended broadband UHF antenna with high inductive input impedance for radiofrequency energy harvesting is presented. It consists of a small feeding loop and a conical radiating monopole. A prototype has been fabricated on a FR4 substrate and tested. Experimental results show a -3 dB power transmission bandwidth of about 130 MHz (860 MHz - 990 MHz).

Electromagnetic analysis of the radiated field by Gas Insulated Switchgears for fault detection

In this work the radiation of the electromagnetic field due to partial discharges throughout the insulation spacer of Gas Insulated Switchgears is investigated. Radiation can be described in terms of resonant modes of the slot between the metallic bolts and of the parallel plate between the metallic flanges. The geometrical characteristics of the spacer, that contribute to the emission of power toward the environment, are investigated.

Modified Honeycomb Photonic Bandgap Fiber Effectively Single-Mode Regime: A Numerical Analysis

An accurate analysis of the single-mode properties of modified honeycomb photonic bandgap fibers with different geometric characteristics has been carried out by calculating the confinement losses of the fundamental and the higher-order modes. Simulation results have shown that confinement loss lower than 0.1 dB/km and an effectively single-mode behaviour over a wavelength range of about 150 nm can be achieved with a 8 air-hole ring fiber

Analisi delle perdite di confinamento nelle fibre a band gap fotonico con reticolo a nido d'ape

The confinement losses in honeycomb photonic band gap fibers are numerically investigated. Honeycomb fibers with both an extra hole and a low refractive index region as defect are considered. It is shown that by means of a proper design, confinement losses lower than 0.1 dB/Km at 1550 nm can be obtained with four rings. INTRODUZIONE La riduzione delle perdite nelle fibre a cristallo fotonico (Photonic Crystal Fibres: PCFs) costituisce un aspetto chiave per la loro applicazione nei sistemi di comunicazione ottici. Nelle PCF l’attenuazione ottica e dovuta in parte al materiale impiegato, in parte alle imperfezioni geometriche ed in parte al numero finito di fori d’aria che possono essere realizzati nella sezione traversa. Quest’ultima tipologia di perdite, dette di sconfinamento, costituiscono il limite inferiore della attenuazione e conseguentemente una loro accurata analisi risulta di fondamentale importanza per il loro progetto ed utilizzo. Le loro proprieta dipendono sensibilmente dal meccanismo di confinamento; nelle PCF puo essere di due tipi: per riflessione totale modificata e per Band Gap fotonico [1]. In questo lavoro verranno presentati i risultati relativi alle perdite di confinamento in fibre con reticolo a nido d’ape (Honeycomb fibres). In queste fibre il confinamento e dovuto a band gap fotonico ed e ottenuto introducendo un difetto nella disposizione regolare dei fori d’aria. Sono state considerate due tipologie di difetto: la prima consiste nell’introdurre un foro d’aria addizionale; la seconda consiste nel ridurre localmente l’indice di rifrazione del materiale che separa i fori d’aria mediante un opportuno drogante. I risultati delle simulazioni mostrano che in questo tipo di fibre le perdite di confinamento dipendono fortemente dalle caratteristiche del difetto, mentre sia la dipendenza dal numero di giri di fori che dal rapporto tra il diametro dei fori ed il passo del reticolo e piu debole di quella delle fibre basate sulla riflessione interna modificata [2]. Cio nonostante, con un’opportuna scelta della dimensione del difetto, del passo del reticolo e delle dimensioni dei fori, si possono ottenere perdite inferiori a 0.1dB/Km nella terza finestra delle telecomunicazioni con soli quattro giri di fori d’aria attorno al difetto. RISULTATI Le sezioni traverse delle fibre prese in esame sono riportate in figura 1. Esse consistono in un reticolo a nido d’ape di fori d’aria. d e il diametro dei fori e Λ il passo del reticolo. I tratteggi differenti delle linee indicano fori appartenenti a giri differenti. Il difetto puo essere ottenuto o introducendo un foro aggiuntivo di diametro dc come mostrato in figura 1(a) oppure riducendo l’indice di rifrazione della zona centrale mediante un opportuno drogaggio come mostrato in figura 1(b). δn=100(nbulk-ncore)/nbulk e il salto d’indice percentuale, essendo ncore l’indice del core e nbulk l’indice del materiale circostante. Nel seguito si assumera ncore =1.45 ed il raggio della regione a basso indice pari a Λ. La figura 2 mostra l’andamento della componente traversa dominante del vettore campo magnetico del modo fondamentale per entrambi i tipi di difetto.