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The periodic evaluation of the Faraday cage efficiency for diagnostic Magnetic Resonance is mandatory by Italian legislation and it is recommended by manufacturers. An inadequate shielding could affect clinical images with artifacts, reducing the quality of examinations. The International reference standard for shielding effectiveness measurements is represented by IEEE Standard 299-2006, but it results poorly applicable in Magnetic Resonance sites. In this study, an alternative approach is proposed to simplify the applicability of the IEEE Standard. The experimental set-up for measurements is composed by a signal generator and a transmitting antenna, coupled with the signal generator. The novelty of the proposed methodology consists in the absence of the receiver antenna; for this purpose, the Magnetic Resonance scanner is used. This approach permits to test the entire Faraday cage by means of a single measure. If the Magnetic Resonance device picks up the radiofrequency signal from outside of the cage, this would be visible on the acquired images as a "zipper" artifact. Four Faraday cages, different in building materials, were tested by using the proposed methodology, and the results were compared with those obtained by using the IEEE Standard. The presence of the "zipper" artifact on the images made us inspect the entire Faraday cage and not just the openings, finding that the radiofrequency signal entered from an area without openings, thus denoting a poor construction of the cage. The proposed methodology provides an immediate evaluation of the shielding efficiency, furnishing information on the entire Faraday cage and not only on its apertures. The method is simple, easily reproducible, and constitutes a valid alternative to the IEEE Standard; in particular, during constancy tests.

In this review, we focus on the recent developments in the Time Domain Nuclear Magnetic Resonance (TD-NMR). The Introduction section describes the methods usually adopted for the assessment of food quality, whereas the second paragraph illustrates the basic physical principles of the TD-NMR technique. In the third section, we discuss the principal application of the TDNMR method in food science. In fact, in the last decades, TD-NMR has become one of the most efficient and advanced techniques for the analysis of food products. In TD-NMR technique, the proton relaxation (transversal relaxation, T2) is monitored, providing information about the mobility of the nuclei. TD-NMR is principally used for monitoring the fat composition of food products, which represents a crucial parameter to be considered for controlling the food properties and improving its quality. This paper will present a summary of the most important applications of low field TD-NMR technique in food science and the results of the most important researches.

National audience; Deux filtres centrés à 110 GHz à base de guides d’ondes intégrés au substrat sont proposés en technologie BenzoCycloButene sur silicium. Unetopologie classique à couplage en iris est utilisée pour la conception d’un filtre Tchebychev avec 10 % de bande passante. Le deuxième filtre repose sur une autre topologie basée sur l’excitation d’un mode de surface à ondes lentes appelé SSPP. Le caractère passe-bas de ce mode et celui passe-haut du guide d’ondes sont associés pour concevoir un filtre de bande passante relative de 40 %. Les résultats de mesure mettent en évidence des pertes d’insertion de 4,5 dB pour le filtre à 10% de bande passante et de 3,45 dB pour le filtre à 40% de bande passante, avec un bon accord avec les simulations électromagnétiques.

International audience; In this paper the design, measurements and retro-simulations of a 110-GHz 5th-order Chebyshev filter, based on substrate integrated waveguide in a 30−μm thick BenzoCycloButene (BCB) above-IC technology, are presented. A center frequency of 101.5 GHz, corresponding to a 8.5-GHz frequency shift towards low frequencies, and 11.8% of fractional bandwidth are measured. The filter presents 4.6-dB of insertion loss and a low return loss of 17.5 dB in the passband. Thanks to optical profilometer measurements, a deformation of the top metallic cover of the SIW structures was observed. Electromagnetic simulations taking this top surface deformation into account allows recovering the measured filter behaviour with the center frequency shift. Thus, this BCB above-IC technology seems promising for the design of passive circuits at higher frequencies, at which substrate heights of 30 μm are more appropriate.

This paper presents studies on natural and anthropogenic radioactivity determination in different mushroom species (Boletus Aereus, Boletus Edulis, Boletus Aestivalis, Agaricus Arvensis, Cantharellus Lutescens, Cantharellus Cibarius, Leccinum Quercinum, Macrolepiota Konradi, Lactarius Deliciosus) collected in Calabria, southern Italy, aimed at determining 137Cs and 40K content in analyzed samples, evaluating the bioconcentration levels and estimating the annual effective dose for ingestion to mushrooms consumers. For all investigated samples, experimental radioactivity results, obtained through High-Purity Germanium (HPGe) gamma spectrometry, were found to be much lower than the specific activity limit set by the international legislation. Information about radionuclides bioaccumulation were given through the calculation of the bioconcentration factor. The effective dose due to the ingestion of mushrooms by adult members of the population was found to be much lower than the recommended level for the public (1 mSv y^(-1)). Results reported in this paper can provide useful information on the environmental risk and can be further used for a radiological mapping of the studied area.

Networking technologies have become increasingly omnipresent over the past two decades. In particular, 5G (fifth generation) is expected to support significantly faster mobile broad-band speeds, lower latencies and hundreds of times more capacity than current 4G (fourth generation) while also enabling the full potential of the Internet of Things. Specifically, the underemployed spectrum in the millimeter-wave (mm-wave) frequency bands (30-300 GHz) might be seen as a potentially profitable solution for achieving the aforementioned goals. In such a context, the switched-beam antenna (SBA) systems have become of great interest because they can achieve high spectral efficiency and increase the capacity of wireless communication systems. More specifically, Butler matrix (BM) is one of the most important multiple beam forming networks, which has been intensively explored and extensively em-ployed in communication systems due to its unique properties as perfect matching, isolation, and equal power division, that can be obtained at the same time.The work achieved in this PhD thesis was focused on the conception of a Butler matrix, for mm-wave applications in SIW topology. Two frequency bands were mainly addressed for that purpose. The first one is the band around 28 GHz, that is suited for 5G, where an ex-tended beam agility concept was introduced for 4ⅹ4 Butler matrix, in PCB-SIW technology, to achieve a better spatial resolution, as compared to a 4ⅹ4 conventional system. The second one is the WR10 band (75 GHz-110 GHz), as well as some extra-bands beyond, for which the use of intermediate packaging platforms, so-called interposers, allow the frequency ris-ing as compared to the conventional PCB technologies. In both, the proposed structures were detailed, theoretical analyses were developed, and simulation and measurement works were carried out, with retro-simulations when needed, which permitted to validate the proposed concepts. One of the main goals of this manuscript is to enhance the spatial antenna cover-age and the performance of the beam forming system as compared to its conventional coun-terpart while keeping almost unchanged the surface (reduced costs and design complexity). Another goal is to study the sensitivity of the system, so that the weak points of the BM are revealed.In the first chapter of this thesis, BM solutions for RF and mm-Wave circuits were present-ed, and beam-steering enhanced ability BMs was detailed. In the second chapter, attention focuses on a detailed sensitivity BM study based on a Monte Carlo approach and a proposed solution for extended beam Butler matrices well suited to SIW technology. In the third chap-ter, the pros and cons of continuous and digital phase shifting are discussed and a 28-GHz ,1-bit, SIW, phase shifter using PIN diodes, is designed and tested as a solution to be used in the extended beam matrix. In the fourth chapter, the design blocks for 28 GHz SIW Butler matrix were introduced and measured, along with the entire BM measurements. In the fifth chapter, benzocyclobutene (BCB) SIW useful for Butler matrix blocks were designed and measured in WR10 and WR5 bands, which show the very interesting performance of such an interposer. Even coupler and crossover were fabricated and measured in WR10 band. As a prospect, the extended beam agility BM concept could be implemented in BCB interposer or other kind of interposers as metallic nanowire membranes (MnM) for sub-THz applications, to test the feasibility., Les technologies réseau sont devenues de plus en plus omniprésentes au cours des deux der-nières décennies. En particulier, la 5G (cinquième génération) devrait supporter des vitesses haut débit nettement plus rapides, des capacités de transfert cent fois plus élevées et des re-tards plus faibles que la générations 4G précédente tout ceci permettant d’utiliser le plein potentiel de l’Internet des Objets. Plus précisément, le spectre sous-employé des bandes de fréquences millimétriques (mm-wave) (30-300 GHz) pourrait être considéré comme une solution potentiellement rentable pour atteindre les objectifs susmentionnés. Dans un tel contexte, les systèmes d’antennes à faisceau commuté sont devenus d’un grand intérêt parce qu’ils peuvent atteindre une plus grande efficacité spectrale et améliorer le bilan de puis-sance des systèmes de communication sans fil. Plus spécifiquement, la matrice de Butler (BM) est l’un des réseaux de formation de faisceaux multiples les plus intéressants, intensi-vement exploré et largement employé dans les systèmes de communication en raison de ses propriétés conjointes d’adaptation, d’isolation, et d’équipartition de puissance.Le travail réalisé dans le cadre de cette thèse de doctorat se concentre sur la conception de matrices de Butler en topologie SIW pour les applications millimétriques. Plusieurs bandes de fréquence ont été abordées à cette fin. La bande autour de 28 GHz intéresse particulière-ment la 5G. Ainsi, le concept de matrice étendue en technologie PCB-SIW est introduit pour la BM 4x4, permettant d’atteindre une meilleure résolution spatiale que le simple système 4x4. La bande WR10 (75 GHz-110 GHz) ainsi que quelques bandes millimétriques au-delà ont également été étudiées. Pour ces dernières, le recours à des substrats intermédiaires dé-diés au millimétrique, appelées interposeurs, s’est révélé indispensable. Dans les deux cas, les structures proposées ont été détaillées, des analyses théoriques élaborées et les résultats de simulation confortés par la mesure, accompagnés de rétro-simulations si besoin, dans le but de proposer des preuves de concept. L’un des principaux objectifs de ce manuscrit est d’améliorer la couverture spatiale de l’antenne et la performance du système de formation du faisceau par rapport à son homologue conventionnel tout en gardant presque inchangé la surface du réseau (coûts réduits et complexité de conception). Un autre objectif est d’étudier la sensibilité du système afin de révéler les points faibles de la matrice de Butler.Le premier chapitre de cette thèse présente un état de l’art des dites matrices, RF et mm-wave , et détaille les solutions permettant d’étendre l’orientation du faisceau. Dans le deu-xième chapitre, l’attention se concentre sur une étude Monte Carlo de sensibilité de la BM quasiment exhaustive. Dans le troisième chapitre, les avantages et inconvénients du chan-gement continu et/ou digital de phase sont discutés et un déphaseur SIW 1-bit, 28-GHz, uti-lisant des diodes PIN, est conçu et testé. Ce déphaseur est un des blocs phare de la matrice de Butler étendue. Le quatrième chapitre présente la conception et la mesure des blocs de la BM à 28 GHz ainsi que l’ensemble des mesures du système complet étendu. Dans le cin-quième chapitre, des guides, coupleurs et crossovers SIW sur interposeur BCB (benzocyclo-butene), tous blocs de la matrice, ont été conçus et mesurés en bande WR10 et WR5. Ils con-firment les performance très intéressante du BCB. En perspective, le concept de matrice de Butler étendue pourrait être mis en œuvre sur interposeur BCB mais aussi dans d’autres technologies telles que les membranes à nanofils métalliques (MnM) pour des applications sous-THz.