Amplitude and Phase Tuning of Microwave Signals in Magnetically Biased Permalloy Structures

In this paper, a permalloy layer has been employed in the fabrication of a coupled line electromagnetic bandgap (EMBG) device to tune both amplitude and phase. A magnetically biased microwave coplanar confi'guration manufactured with evaporated permalloy has been measured, and a circuit modelling has been studied to evaluate the measured effects in terms of variable attenuation and phase shift. Starting from a permalloy made by the mixture 80% nickel and 20% iron content, we fabricated an electromagnetic bandgap (EMBG) structure based on a periodic arrangement of single sections of a transmission line with variable impedance, also including a central region with coupled lines. The bandpass characteristics of the EMBG device can be tuned by changing permalloy's permeability through the application of a DC magnetic fi'eld H-0 (parallel to the plane of the structure). In particular, using a magnetic fi'eld up to 3000 Oe, it was possible to change the phase by ca. 45 degrees and the amplitude by ca. 7 dB in the X band

Very large phase shift of microwave signals in a 6 nm Hf x Zr 1− x O 2 ferroelectric at ±3 V

In this letter, we report for the first time very large phase shifts of microwaves in the 1–10 GHz range, in a 1 mm long gold coplanar interdigitated structure deposited over a 6 nm Hf x Zr1−x O2 ferroelectric grown directly on a high resistivity silicon substrate. The phase shift is larger than 60° at 1 GHz and 13° at 10 GHz at maximum applied DC voltages of ±3 V, which can be supplied by a simple commercial battery. In this way, we demonstrate experimentally that the new ferroelectrics based on HfO2 could play an important role in the future development of wireless communication systems for very low power applications

Procedure in sala dialisi durante l’emergenza Covid-19

Scopo Scopo del presente documento \ue8 definire modalit\ue0 omogenee di gestione del paziente dializzato a partire dalla comparsa di casi accertati nella popolazione italiana di infezione da nuovo Coronavirus 2019-nCoV (Covid-19). Applicabilit\ue0 Il presente documento si applica alle attivit\ue0 di sala dialitica di seguito descritte. Il documento \ue8 attualmente in applicazione presso i due presidi ospedalieri dell\u2019ASST Santi Paolo e Carlo e relativi CAL Mompiani e Rozzano. Descrizione Questo documento espone le misure di prevenzione e di controllo della diffusione dell\u2019infezione da nuovo Coronavirus, attuate dal giorno 24/02/2020 dal personale dell\u2019unit\ue0 operativa dialisi al fine di limitare la trasmissione da persona a persona. Le indicazioni che seguono hanno quindi l\u2019obiettivo di garantire l\u2019uniformit\ue0 di comportamento degli operatori sanitari nel confronto dei pazienti afferenti al centro, al fine di identificare e gestire i casi sospetti, probabili e confermati da infezione da Coronavirus. Tutti i pazienti che giungono in ospedale per eseguire la seduta emodialitica vengono considerati \u201cpotenzialmente\u201d infetti da Covid-19 e, pertanto, tutti gli operatori e tutti i pazienti devono seguire le indicazioni del protocollo sui dispositivi di protezione individuale (DPI): l\u2019igiene delle mani, l\u2019utilizzo della cuffia, mascherina chirurgica occhiali o visiera, guanti e camice come da procedure

Electromagnetic energy harvesting based on HfZrO tunneling junctions

HfZrO ferroelectrics with a thickness of 6 nm were grown directly on Si using atomic layer deposition, top and bottom metallic electrodes being subsequently deposited by electron-beam metallization techniques. Depending on the polarity of the ±10 V poling voltages, the current–voltage dependence of these tunneling diodes shows a rectifying behavior for different polarizations, the ON–OFF ratio being about 104. Because the currents are at mA level, the HfZrO tunneling diodes coupled to an antenna array can harvest electromagnetic energy at 26 GHz (a bandwidth designated for internet of things), with a responsivity of 63 V W−1 and a NEP of 4 nW/Hz0.5

MoS2 radio: detecting radio waves with a two-dimensional transition metal dichalcogenide semiconductor

In this paper, we designed, fabricated and tested a microwave circuit based on a MoS2 self-switching diode. The MoS2 thin film (10-monolayers nominal thickness) was grown on a 4 inch Al2O3/high-resistivity silicon wafer by chemical vapor deposition process. The Raman measurements confirm the high quality of the MoS2 over the whole area of the 4 inch wafer. We show experimentally that a microwave circuit based on a few-layers MoS2 self-switching diode fabricated at the wafer level is able to detect the audio spectrum from amplitude-modulated microwave signals in the band 0.9–10 GHz, i.e. in the frequency range mostly used by current wireless communications. In particular, the 900 MHz band is widely exploited for GSM applications, whereas the 3.6 GHz band has been identified as the primary pioneer band for 5G in the European Union

Harvesting electromagnetic energy in the V-band using a rectenna formed by a bow tie integrated with a 6-nm-thick Au/HfO2/Pt metal-insulator-metal diode

In this paper, the first demonstration of a bow-tie antenna integrated with a metal-insulator-metal (MIM) diode for electromagnetic energy harvesting in the V-band (i.e., 40-75 GHz) is presented. We have designed, simulated, fabricated, and fully characterized a 60-GHz rectifying antenna (rectenna) based on a vertical Au-HfO2-PtMIM diode with reduced differential resistance. The dielectric used for the MIM structure is a 6-nm-thick amorphous HfO2 grown by atomic layer deposition. For the fabricated MIM device, we report here a current density of 3 x 10(4) A/cm(2) that exceeds the previous values presented in the literature. The vertical MIM-based rectenna is able to efficiently harvest up to 250 mu V from an impinging modulated millimeter-wave signal with -20 dBm of available power, thus offering a voltage responsivity of over 5 V/W. The reported results indicate that the proposed approach is well suited for future low-power solutions much sought after for the energetically autonomous 5G terminal equipment

Design of a 24-GHz dual-polarized rectenna integrated on silicon

This paper presents the design of an integrated and differential rectenna on silicon, operating at 24 GHz. The antenna is dual-polarized and composed by four patches on a synthetized low effective permittivity dielectric. The substrate is a structure composed of three layers of high-resistivity silicon (εr = 11.9) where the central layer has an air cavity equal to the dimensions of the antennas. The feeding solution is performed by planar microstrip lines with inset feeds. A shunt configuration was chosen for the rectifiers with GaAs diodes. The silicon substrate assures the complete integration for on-chip systems and despite the lossy material chosen as substrate, each patch antenna presents 83% of radiation efficiency with a maximum gain of 4.82 dBi. The overall efficiency of the rectenna is 43% at a received power level of 14 dBm

Graphene as a high impedance surface for ultra-wideband electromagnetic waves

The metals are regularly used as reflectors of electromagnetic fields emitted by antennas ranging from microwaves up to THz. To enhance the reflection and thus the gain of the antenna, metallic high impedance surfaces (HIS) are used. HIS is a planar array of continuous metallic periodic cell surfaces able to suppress surface waves, which cause multipath interference and backward radiation in a narrow bandwidth near the cell resonance. Also, the image currents are reduced, and therefore the antenna can be placed near the HIS. We demonstrate that graphene is acting as a HIS surface in a very large bandwidth, from microwave to THz, suppressing the radiation leakages better than a meta

Numerical analysis of an innovative energy-harvesting system in the infrared region

In the field of renewable energy sources, the sun has rightly a predominant role and many techniques have been developed so far to exploit solar energy for power supply and heating. In this paper, we propose an in-depth investigation on a new solution to deploy THz sun radiation in the infrared (IR) region: an array of planar bow-tie antennas with misaligned arms is designed, and tunnel diodes are used to rectify THz power. A theoretical estimation of the overall performance is discussed, together with technological constraints and future researche