Comptes Rendus Physique最新文献

{"title":"Compatibility between EESS (passive) in band 23.6–24 GHz and 5G in band 24.25–27.5 GHz","authors":"T. Caillet","doi":"10.5802/CRPHYS.67","DOIUrl":"https://doi.org/10.5802/CRPHYS.67","url":null,"abstract":"The 24.25–27.5 GHz band was allocated to IMT (International Mobile Telecommunication) during the World Radiocommunication Conference (WRC) after studies were elaborated between this potential allocation and the services in adjacent band and in particular with Earth Exploration by satellite in adjacent band. Several studies were evaluated during the WRC-19 cycle. This document describes only the studies undertaken by some European states for the protection of Earth exploration by satellite. The elements provided in this document are the basis of the European position for WRC-19 on the protection of passive EESS in 23.6–24 GHz.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"57 1","pages":"1-11"},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73818389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-beam modulated metasurface antenna for 5G backhaul applications at K-band","authors":"J. Ruiz-García, M. Faenzi, A. Mahmoud, M. Ettorre, P. Potier, P. Pouliguen, R. Sauleau, D. González-Ovejero","doi":"10.5802/CRPHYS.62","DOIUrl":"https://doi.org/10.5802/CRPHYS.62","url":null,"abstract":"We explore the use of a new modulated metasurface (MTS) antenna topology as solution for wireless backhaul at K band. The proposed structure is composed of a quasi-optical beamformer, which feeds the modulated MTS radiating aperture. These two elements are vertically stacked in a two-layer pillbox architecture to produce a very compact antenna. Furthermore, our design is able to provide several beams at different pointing angles and, hence, it offers the possibility of discrete beam steering by beam switching. The employment of a modulated MTS and the compactness given by the pillbox approach lead to a high-gain and low-profile antenna that could be an appealing solution for mobile backhaul networks.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42121664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bandpass NGD function design for 5G microwave signal delay synchronization application","authors":"S. Lalléchère, L. Rajaoarisoa, L. Clavier, Raul Sanchez Galan, B. Ravelo","doi":"10.5802/CRPHYS.68","DOIUrl":"https://doi.org/10.5802/CRPHYS.68","url":null,"abstract":". Thispaperintroducesadesignmethodofsimplebandpass(BP)negativegroupdelay(NGD)topology. The fundamental specifications of BP NGD function are defined. The NGD passive topology consists of parallel resistance associated with an open-ended microstrip stub. The NGD properties and characterization with respect to the constituting stub parameters are established. The validations are performed with theoretical calculated and simulated GD, transmission and reflection coe ffi cients. The BP NGD circuit can be useful for the improvement of phase linearity and GD equalization of future 5G microwave devices.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43396771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modeling of downlink electromagnetic wave exposure generated by 5G beamforming antennas","authors":"N. Noé, F. Gaudaire","doi":"10.5802/CRPHYS.61","DOIUrl":"https://doi.org/10.5802/CRPHYS.61","url":null,"abstract":"Abstract: In this paper di erent scenarios were compared for the numerical modeling of electromagnetic wave exposure to beamforming antennas. These scenarios range from the simplest (using an averaged radiation pattern) to an almost realistic one (MU-MIMO beamforming taking into account users locations) with intermediate ones. The results underline the in uence of the environment around the antennas on the distribution of the electric eld.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"16 1","pages":"1-10"},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90713947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced integrated multiband HPM radiator, combining a hyperband source with a high-Q frequency selective surface","authors":"F. Albarracin-Vargas, Felix Cabrera Vega, C. Kasmi, David Martinez, L. Fichte","doi":"10.5802/CRPHYS.63","DOIUrl":"https://doi.org/10.5802/CRPHYS.63","url":null,"abstract":"This work presents advances on the development of a resonant radiator, obtained as the augmentation of a conventional Impulse Radiating Antenna (IRA) with a Frequency Selective Surface (FSS), in the L-band. An improved passband-type FSS is obtained by exploring the Multiple Split Ring Resonators (MCSRR) unit cells to obtain a higher Q-factor radiator. The effects of a multiband and of a tunable FSS’s are also studied and verified via simulations. A variety of applications are enabled by modifying the UWB waveform from the IRA into a damped sinusoidal from the combined radiator like IEMI testing, hardening of infrastructures, cloaking of wide aperture radiators, among other. The system analysis methodology can also be applied to other FSS geometries, or the combinations of various of them.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"17 1","pages":"1-10"},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86225512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The search for manganese incorporation in MoSe 2 monolayer epitaxially grown on graphene","authors":"M. Dau, C. Vergnaud, A. Marty, F. Bonell, H. Boukari, C. Paillet, B. Hyot, H. Okuno, P. Mallet, J. Veuillen, O. Renault, M. Jamet","doi":"10.5802/CRPHYS.69","DOIUrl":"https://doi.org/10.5802/CRPHYS.69","url":null,"abstract":"The introduction of magnetism in two-dimensional (2D) materials represents an intense field of research nowadays and the quest to reach above-room-temperature ordering temperatures is still underway. Intrinsic ferromagnetism was discovered in 2017 in CrI3 and Cr2Ge2Te6 in the monolayer form with low Curie temperatures. An alternative method to introduce magnetism into conventional 2D materials is substitutional doping with magnetic impurities similarly to three-dimensional diluted magnetic semiconductors. The case of Mn-doped transition metal dichalcogenide (MoS2, MoSe2, WS2, WSe2) monolayers is very interesting because combining out-of-plane ferromagnetism and valley contrast leads to ferrovalley materials. In this work, we focus on the incorporation of Mn in MoSe2 by molecular beam epitaxy on graphene which has been rarely addressed up to now. By using a multiscale characterization approach, we demonstrate that Mn atoms are incorporated into the MoSe2 monolayer up to 5 atomic percent. However, when incorporated into the film, Mn atoms tend to diffuse to the grain edges forming undefined MoxMnySez phase at grain boundaries after completion of the MoSe2 monolayer. This segregation leaves the crystalline and electronic structure of MoSe2 unmodified. Above 5%, the saturation of Mn content in MoSe2 leads to the formation of epitaxial MnSe clusters.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43544530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysing discrete dislocation data using alignment and curvature tensors","authors":"Benedikt Weger, Satyapriya Gupta, T. Hochrainer","doi":"10.5802/CRPHYS.60","DOIUrl":"https://doi.org/10.5802/CRPHYS.60","url":null,"abstract":"Analysis of large scale discrete dislocation data requires the characterisation of complex dislocation networks by suitable average quantities. In the current work, we suggest dislocation alignment tensors and closely related curvature tensors as easily extractable and intelligible measures of geometrical and topological characteristics of dislocation distributions. We provide formulae for extracting these measures from discrete dislocation data based on straight segments. Examples for interpreting and visualising these measures are provided for a simple configuration and two more involved results from discrete dislocation simulations. We suggest the alignment and curvature tensors for wider use in plasticity research.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"77 1","pages":"1-18"},"PeriodicalIF":1.4,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81277190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrafast dynamics with time-resolved ARPES: photoexcited electrons in monochalcogenide semiconductors","authors":"Zhesheng Chen, J. Caillaux, Jiuxiang Zhang, E. Papalazarou, Jingwei Dong, J. Rueff, A. Taleb-Ibrahimi, L. Perfetti, M. Marsi","doi":"10.5802/CRPHYS.57","DOIUrl":"https://doi.org/10.5802/CRPHYS.57","url":null,"abstract":"Time-resolved ARPES makes it possible to directly visualize the band dispersion of photoexcited solids, as well as to study its time evolution on the femtosecond time scale. In this article, we show how this technique can be used to monitor the ultrafast hot carrier dynamics and the conduction band dispersion in two typical monochalcogenide semiconductors: direct band gap, n-type indium selenide and indirect band gap, p-type germanium selenide. With this approach, one can directly estimate the effective electron masses of these semiconductors. Moreover, the dynamics of hot electrons in the two semiconductors are analyzed and compared. Our findings provide valuable information for the use of monochalcogenide semiconductors in future optoelectronic devices.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"64 1","pages":"1-8"},"PeriodicalIF":1.4,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87153013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Étude théorique de la compression de spin nucléaire par mesure quantique non destructive en continu","authors":"Alan Serafin, Y. Castin, Matteo Fadel, Philipp Treutlein, A. Sinatra","doi":"10.5802/CRPHYS.71","DOIUrl":"https://doi.org/10.5802/CRPHYS.71","url":null,"abstract":"Nous proposons de tirer parti du tres faible couplage du spin nucleaire de l'helium 3 fondamental a son environnement pour produire des etats quantiques macroscopiques a tres longue duree de vie, ici des etats comprimes du spin nucleaire, dans un gaz en cellule a temperature ordinaire. Pour effectuer une mesure quantique non destructive sur une composante transverse du spin nucleaire collectif prealablement polarise, on allume temporairement une decharge dans le gaz, ce qui peuple l'etat metastable de l'helium 3. Le spin collectif correspondant au niveau $F=1/2$ des metastables s'hybride alors legerement avec celui des fondamentaux par collision d'echange de metastabilite. Il reste a mesurer en continu le champ lumineux sortant d'une cavite optique, ou il a interagi de maniere dispersive avec le spin collectif du metastable, pour acceder aux fluctuations du spin nucleaire. Dans un modele de trois spins collectifs couples (nucleaire, du metastable et de Stokes de la lumiere) dans l'approximation de Primakoff, et pour deux schemas de mesure, nous calculons les moments de la composante comprimee $I_z$ du spin nucleaire collectif conditionnes au signal optique moyenne sur le temps d'observation $t$. Dans le schema de comptage de photons, nous retrouvons que l'observable comprimee est $I_z^2$ plutot que $I_z$. Dans le schema de detection homodyne, nous resolvons analytiquement l'equation stochastique sur l'etat du systeme conditionne a la mesure ; la moyenne conditionnelle de $I_z$ depend lineairement du signal et la variance conditionnelle de $I_z$ n'en depend pas. La variance conditionnelle decroit comme $(Gamma_{rm sq}t)^{-1}$, ou le taux de compression $Gamma_{rm sq}$, que nous calculons explicitement, est lineaire en l'intensite lumineuse dans la cavite a faible couplage atome-champ et sature a fort couplage au taux effectif d'echange de metastabilite dans l'etat fondamental, proportionnel a la densite d'atomes metastables. Enfin, nous tenons compte de la desexcitation des metastables sur les parois, qui induit une decoherence du spin nucleaire avec un taux ramene $gamma_alpha$. Elle impose une limite $propto (gamma_alpha/Gamma_{rm sq})^{1/2}$ sur la variance conditionnelle atteinte en un temps $propto (gamma_alphaGamma_{rm sq})^{-1/2}$.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"31 1","pages":"1-35"},"PeriodicalIF":1.4,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89917248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-situ evaluation of exposure induced by 5G antennas in the 3.4–3.8 GHz band","authors":"E. Conil, J.-B. Agnani","doi":"10.5802/CRPHYS.65","DOIUrl":"https://doi.org/10.5802/CRPHYS.65","url":null,"abstract":"In this paper, exposure induced in the vicinity of four pilot sites with 5G NR antennas in the 3.4–3.8 GHz band is assessed in-situ. Different manufacturers of antennas and different types of antenna are considered. Measurements are performed without any traffic, with continuous traffic in one direction and with on demand download of files. These measurements highlighted the variation in the level of exposure depending on use and led to the proposal of a new indicator to calculate the actual exposure created by 5G networks with steerable beams. This indicator results in a reduction factor that is used to assess the exposure in live conditions based on the configured maximum antenna power.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"28 1","pages":"1-11"},"PeriodicalIF":1.4,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73281389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}