Search results for "Volt"
showing 10 items of 2187 documents
Experimental Study of the Multipactor Effect in a Partially Dielectric-Loaded Rectangular Waveguide
2019
This letter presents the experimental study of the multipactor threshold in a partially dielectric-loaded rectangular waveguide, whose results validate a multipactor model recently developed by the authors, which includes the charge distribution appearing on the dielectric surface during the multipactor discharge. First, the variation of the multipactor RF voltage threshold has been theoretically analyzed in different waveguide configurations: in an empty waveguide, and also in the cases of a one-sided and two-sided dielectric-loaded waveguides. To reach this aim, an in-house Monte Carlo simulation tool has been developed. The Secondary Electron Yield (SEY) of the metallic and dielectric ma…
Multipactor RF Breakdown in Coaxial Transmission Lines With Digitally Modulated Signals
2016
The aim of this paper is the study of the RF multipactor breakdown in coaxial transmission lines excited by a single carrier with a digitally modulated signal. Employing an in-house developed code, numerical simulations are performed to determine the RF multipactor voltage threshold for several digitally modulated signals under different modulations schemes: quadrature phase-shift keying, 16-quadrature amplitude modulation, 16-amplitude and phase-shift keying, and 32-amplitude and phase-shift keying. Moreover, a coarse method based on the envelope integration to determine the RF multipactor voltage threshold when involving arbitrary digital modulations is also presented. These results are a…
High power analysis and design of dual-mode channel filters
2009
In this paper, we present two dual-mode channel filter topologies which are able to withstand more than 600 W in Ku-Band. The two different designs (one with elliptical cavities and the other one with rectangular cavities) implement the same transfer function: four order, elliptical response centered in 12 GHz, with 40 MHz bandwidth and two transmission zeros. It is shown that the critical dimensions for the power-handling of these filters are the dimensions of the input-output irises. In fact, in order to rigorously obtain these conclusions and to reach these high-power levels (including margins), it is essential to use the advanced numerical techniques described in the paper to predict th…
Multipactor Effect in a Parallel-Plate Waveguide Partially Filled With Magnetized Ferrite
2014
The aim of this paper is the analysis of the multipactor effect in a parallel-plate waveguide when a ferrite slab, transversally magnetized by a static magnetic field parallel to the waveguide walls, is present. Employing an in-house developed code, numerical simulations are performed to predict the multipactor radio frequency voltage threshold in such a ferrite-loaded waveguide. Variations of the ferrite magnetization field strength and the ferrite slab height are analyzed. Effective electron trajectories are also shown for a better understanding of the breakdown phenomenon, finding different multipactor regimes.
Time evolution of an electron discharge in a parallel-plate dielectric-loaded waveguide
2006
The objective of this letter is to study the time evolution of a multipactor discharge in a simple dielectric waveguide structure. In particular, the investigation is performed on the case of a parallel-plate waveguide structure partially filled with a dielectric layer. The main consequence of the specific case studied in this letter is the fact that the dielectric layer charges negatively, allowing a negative static field to build up. This dc field eventually leads to a single-surface multipactor in the metallic surface before finally turning off the electron discharge.
Experimental Analysis of the Multipactor Effect With RF Pulsed Signals
2015
The main goal of this letter is the analysis of the multipactor effect within a coaxial waveguide excited by an RF pulsed signal. The variation of the multipactor RF voltage thresholdwiththe ON interval length of the pulse has been analyzed. To reach this aim, an in-house multipactor simulation code based on the Monte-Carlo algorithm has been implemented. The numerical simulations show that the multipactor RF voltage threshold increases as the ON pulse interval diminishes. In addition, an experiment was carried out to validate the proposed theoretical model, and demonstrating the excellent agreement between the theory and the experimental data. Finally, the results are compared with the 20-…
Ferrocenyl glycopeptides as electrochemical probes to detect autoantibodies in multiple sclerosis patients' será
2008
Abstract Glycopeptide analogues of CSF114(Glc), modified at N-terminus with new ferrocenyl carboxylic acid and a new ferrocenyl-thiphosphino amino acid, were used to implement a new electrochemical biosensor for autoantibody detection in multiple sclerosis. The ferrocenyl moiety of these "electrochemical probes" did not affect autoantibody recognition both in SP-ELISA and in inhibition experiments. By electrochemical monitoring the interactions of the modified peptides Fc-CSF114(Glc) and 4-FcPhP(S)Abu-CSF114(Glc) with the autoantibodies, we demonstrated that autoantibodies could be detected with a sensitivity comparable to ELISA method. The new electrochemical probes can be proposed to char…
A 3.3 V Output Voltage Optical Plasmonic Solar Energy Harvester
2021
In this paper, for the first time, the design of a solar energy-harvester (EH) based on plasmonic optical nanorectennas and without the step-up converter is presented. The novel optical harvester with a 49497∗14286 nanoarray of about 21,21 mm2 presents an output voltage value of 3.3 V and an output current of 10 mA.
A new CdTe/ZnO columnar composite film for Eta-solar cells
2002
Abstract First results of CdTe deposition on ZnO films consisting of free standing single crystalline columns of several micrometers height and ∼100– 200 nm diameter are presented. The ZnO films have been obtained by electrochemical deposition on conductive glass. Morphology, structural and optical properties of the nanostructured columnar CdTe/ZnO composite films have been studied. The cadmium telluride ( 40 nm thick) deposited by vapor-phase epitaxy under dynamical vacuum is lining the ZnO columns as a continuous smooth thin film with conformal coverage. The polycrystalline CdTe layer is a mixture of cubic and hexagonal phases and is semiconductor with a direct band gap optical transition…
Ligand removal from soluble CdTe nanocrystals evidenced by time-resolved photoluminescence spectroscopy
2008
We present experimental studies on the effect of pyridine treatment on the optical properties of ligand-stabilized colloidal CdTe nanocrystals. We demonstrate, by quasi-stationary and time-resolved photoluminescence (PL) spectroscopy, a drastic reduction in the PL lifetime and a concomitant decrease in the PL yield by more than 90% when dissolving the nanocrystals in pyridine. The pyridine solvent efficiently removes the ligand shell and thus enables a rapid energy transfer from the quantum dot to optically dark surface states or into the solvent. The demonstrated removal of the ligand shell is a key step towards integrating such CdTe nanocrystals in hybrid organic/inorganic nanocomposites,…