A Cavity-Backed Shorted Annular Patch (SAP) Array for Mid-Range V-Band Backhauling Applications

This paper presents a new improved gain array configuration well suited for mid-range V-band backhauling applications. The proposed solution is based on a cavity-backed shorted annular patch (SAP) antenna loaded with a parasitic patch element for gain maximization. This solution is proved by designing and measuring a 4 × 4 array which presents a reflection coefficient bandwidth covering the frequencies from 58.7 to 63.25 GHz (7.6% at 60 GHz). The experimentally validated array gain is equal to 18 dBi corresponding to 37.9% of aperture efficiency. The antenna and array configurations presented in this paper are optimized to minimize the manufacturing cost and complexity. This result is achieved through a novel beamforming network (BFN) configuration, implemented using a dual-layer substrate-integrated waveguide (SIW) technology, and partly integrated on the array aperture. The achieved results demonstrate how the performance of the cavity backed SAP array is comparable to the ones achieved with more complex and expensive solutions

ANALYSIS OF LOSSY SIW STRUCTURES BASED ON THE PARALLEL PLATES WAVEGUIDE GREEN'S FUNCTION

Abstract—In this paper, a full-wave analysis technique of lossy substrate integrated waveguides, based on the dyadic Green’s function of the parallel plate waveguide, is presented. The field inside the waveguide is expressed in terms of cylindrical vector wave-functions and the finite conductivity of the top and of the bottom plates, and of the metallic vias are taken into account. Losses into the dielectric substrate are also included. Coaxial ports are considered as sources and self and mutual admittances are evaluated. Cases of practical structure taken from literature are presented showing a very good agreement with the most used commercial software. 1

Reflector antenna analysis for 5G applications

Este paper tiene por objetivo principal el análisis de antenas tipo reflector para aplicaciones 5G. El diseño inicia con el estudio de un reflector parabólico tipo offset, que es la base para el estudio del reflector tipo Cassegrain para el cual tenemos en cuenta las investigaciones presentes en la literatura. El objetivo es desarrollar un modelo analítico que nos ayude a entender su funcionamiento. Las curvas de proyección son indicadas en función de la geometría, de la relación entre distancia focal y diámetro F /D, de la variación del modelo de radiación de alimentación, es decir de la posición del alimentador. Algunos modelos analíticos han sido hechos en función de la óptica geométrica y la distribución de corriente superficial. Finalmente se desarrolla un software en Matlab, usando los modelos antes estudiados, con los cuales es posible calcular algunos parámetros importantes del reflector, como; ganancia, directividad, componentes co y cross-polares en manera absoluta y normalizada. Para hacer la validación de todo el estudio realizado se hace una comparación entre el análisis con el software desarrollado en Matlab y las simulaciones hechas en TICRA-GRASP

Desarrollo de un software especializado para el diseño de antenas tipo reflector para aplicaciones 5G en banda E

Desde el descubrimiento de la propagación de las ondas electromagnéticas, las antenas de tipo reflector son ampliamente utilizadas en campos como la radioastronomía, la comunicación microondas y la localización satelital. Estas aplicaciones han permitido el desarrollo de técnicas de análisis y cálculos más precisos, consiguiendo de esta forma mayor ganancia en la antena y optimización en la iluminación de la misma. Para aumentar esta recepción por ejemplo los radiotelescopios utilizan grandes reflectores que dirigen la energía receptada hasta un simple alimentador (feed). La forma más común de reflector es el paraboloide, ya que puede focalizar la onda plana en un solo punto llamado foco. Las antenas de tipo reflector pueden tener muchas configuraciones, pero en este artículo citaremos principalmente las de tipo reflector para aplicaciones 5G. El diseño inicia con el estudio de un reflector parabólico tipo offset, que es la base para el estudio del reflector tipo Cassegrain. Se realizan dos modelos analíticos en función de la óptica geométrica y la distribución de corriente superficial. Finalmente se desarrolla un software en Matlab, mediante el cual es posible calcular parámetros importantes del reflector, como: ganancia, directividad, componentes co y cross-polar en manera absoluta y normalizada. La validación de todo el estudio realizado se hace por medio de una comparación entre Matlab y simulaciones hechas en TICRA-GRASP

A Gain Levelling Technique for On-Chip Antennas Based on Split-Ring Resonators

This paper introduces a gain enhancement technique for monolithically integrated antennas. Such devices can suffer from gain dips within their operating bandwidth due to standing waves arising in the die or caused by interactions with other on-chip components. In this work, it is shown how these effects can be significantly mitigated by parasitically coupling square Split Ring Resonators (SRR) to the fed antenna. The SRRs geometry and their coupling with the master antenna can be set in such a way that they create an additional resonance that cancels gain drops and improves impedance matching. The proposed configuration has been validated using a W-band monopole antenna in a standard $0.13~\mu \text{m}$ SiGe BiCMOS process. Thanks to the proposed approach, it was possible to compensate a gain drop of about 7 dB at about 85 GHz. As a result, the experimental assessment showed a maximum measured antenna gain of 1.61 dB at 81.5 GHz and an operating bandwidth from 77 to 87 GHz

Influence of γ-glutamyltransferase and alkaline phosphatase activity on in vitro fertilisation of bovine frozen/thawed semen

AbstractThe aim of this work was to evaluate whether the residual amount of γ-glutamyl-transferase (GGT) and alkaline phosphatase (ALP) in bovine sperm after freezing/thawing is correlated with fertility parameters, including blastocyst rates after in vitro fertilisation (IVF). The enzyme activities were determined in both spermatozoa and supernatant after centrifugation. While ALP was only correlated with sperm viability, GGT activity was correlated with sperm motility (rs = .4; p < .05) both in sperm and supernatant. Interestingly, GGT activity was also correlated with cleavage (rs = .5; p < .05 and .8; p < .01, for sperm and supernatant respectively) and blastocyst (rs = .6 and .9, for sperm and supernatant respectively; p < .01) rates obtained after IVF. These results suggest that GGT could play an important role in the protection of sperm against oxidative stress and could be considered a reliable marker to assess frozen/thawed sperm quality in bovine

Small leucine rich proteoglycans are differently distributed in normal and pathological endometrium

BACKGROUND: During the woman's fertile period, the non-pregnant uterus is subject to constant cyclic changes. The complex mechanisms that control the balance among proliferation, differentiation, cell death and the structural remodeling of the extracellular matrix can contribute to the benign or malignant endometrial pathological state. The small leucine-rich proteoglycans (SLRPs) are important components of cell surface and extracellular matrices. MATERIALS AND METHODS: Using immunohistochemistry, we showed that the distribution patterns of SLRPs were completely modified in the pathological compared to normal endometrium. RESULTS: The expression of SLRPs was low/absent in all endometrial pathologies examined compared to normal endometrium. We observed an increase of lumican from proliferative to secretory phase of the endometrium and a decrease of fibromodulin, biglycan and decorin. In menopause endometrial tissue, the level of expression of fibromodulin, biglycan, decorin and lumican dramatically decreased. CONCLUSION: The results revealed the prominence and importance of proteoglycans in the tissue architecture and extracellular matrix organization

Extreme Longevity: Analysis of the Direct or Indirect Influence of Environmental Factors on Old, Nonagenarians, and Centenarians in Cilento, Italy

Longevity is rightly considered one of the greatest achievements of modern society, an achievement understood as the possibility of increasing the healthy part of life and not only its full duration. This study investigated the phenomenon of regional longevity in Cilento by analyzing the association between longevity indicators and some environmental factors, in order to understand if factors such as altitude, climate, UNESCO protected areas, and hinterland can directly or indirectly influence the measure of healthy living and lead to longevity. Demographic and environmental data were collected through the Archives of the Cilento municipalities, the National Institute of Statistics, the Italian Institute for Environmental Protection and Research, and the Italian National Commission for UNESCO. The Geographically Weighted Regression were used to determine the association between longevity indicators and environmental factors. Correlation analysis between the longevity indicators was investigated in order to have a complete picture of longevity in Cilento. It was discovered that Cilento longevity is mainly found in the central area of the territory and from there, by age groups, it widens towards the south-eastern area. This designated area is part of the hilly area of the Cilento, at an altitude between 400 and 700 m above sea level. The towns of this area are part of the UNESCO heritage and are characterized by a transitional climate between Mediterranean and temperate climate. Moreover, the correlation analysis between the six indicators of longevity has confirmed a linear relationship between the six variables and this indicates that in the years to come there will be the probabilities of a generational turn over between the old, great old, nonagenarians and current centenarians, provided that the SARS-CoV-2 pandemic subsides