Добірка наукової літератури з теми "Air-Filled SIW"

This study showcases the creation of an innovative textile antenna sensor that utilizes a resonant cavity for the purpose of liquid characterization. The cavity is based on circular substrate integrated waveguide (SIW) technology. A hole is created in the middle of the structure where a pipe is used to inject the liquid under test. The pipe is covered by a metal sheath to enhance the electromagnetic field’s penetration of the tube, thus increasing the device’s sensitivity. The resonance frequency of the proposed system is altered when the liquid under test is inserted into the sensitive area of the structure. The sensing of the liquid is achieved by the measurement of its dielectric properties via the perturbation of the electric fields in the SIW configuration. The S11 measurement enables the extraction of the electromagnetic properties of the liquid injected into the pipe. Specifically, the dielectric constant of the liquid is determined by observing the resonance frequency shift relative to that of an air-filled pipe. The loss tangent of the liquid is extracted by comparing the variation in the quality factor with that of an air-filled pipe after eliminating the inherent losses of the structure. The proposed SIW antenna sensor demonstrates a high sensitivity of 0.7 GHz/Δεr corresponding to a dielectric constant range from 4 to 72. To the best of our knowledge, this article presents for the first time the ability of a fully textile SIW cavity antenna-based sensor to characterize the dielectric properties of a liquid under test and emphasizes its differentiating features compared to PCB-based designs. The unique attributes of the textile-based antenna stem from its flexibility, conformability, and compatibility with various liquids.

Substrate-integrated waveguide (SIW) is a modern day (21st century) transmission line that has recently been developed. This technology has introduced new possibilities to the design of efficient circuits and components operating in the radio frequency (RF) and microwave frequency spectrum. Microstrip components are very good for low frequency applications but are ineffective at extreme frequencies, and involve rigorous fabrication concessions in the implementation of RF, microwave, and millimeter-wave components. This is due to wavelengths being short at higher frequencies. Waveguide devices, on the other hand, are ideal for higher frequency systems, but are very costly, hard to fabricate, and challenging to integrate with planar components in the neighborhood. SIW connects the gap that existed between conventional air-filled rectangular waveguide and planar transmission line technologies including the microstrip. This study explores the current advancements and new opportunities in SIW implementation of RF and microwave devices including filters, multiplexers (diplexers and triplexers), power dividers/combiners, antennas, and sensors for modern communication systems.

In this paper, a broadband and simple vertical transition between substrate integrated waveguide and standard air-filled rectangular waveguide is design and experimentally verified. From full-wave simulation of the structure, a relative bandwidth of 19.5% in W-band with return loss better than 20dB is reached. Then, five copies of back-to-back connected transitions are fabricated on RT/Duroid 5880 substrate. The experimental results show that the transition pairs have an average of 15% relative bandwidth with return loss better than 12dB and insert loss lower than 1.2dB. To explain the differences between simulated and tested results, an error analysis is presented.

La technologie des guides d’ondes et celle des circuits imprimés (PCB en anglais) constituent deux jalons dans l’histoire de l’ingénierie des micro-ondes. Les guides d’ondes sont à l’origine de différents types de dispositifs passifs tels que les antennes ou les filtres alors que la technologie des PCB a permis d’intégrer les composants actifs tels que les amplificateurs ou les mélangeurs sur de petits volumes. Les composants passifs basés sur les guides d’ondes présentent des avantages tels que de faibles pertes d’insertion, une capacité de tenue en puissance élevée et un blindage intrinsèque. La technologie des guides d’ondes intégrés au substrat (SIW en anglais) proposée dans les années 2000 a réduit la taille des guides d’ondes volumiques en combinant deux technologies : les guides d’ondes métalliques et les PCBs. Elle permet d’obtenir des pertes d’insertion relativement faibles, un blindage intrinsèque et de faibles dimensions. Le SIW simplifie l’intégration des dispositifs passifs basés sur des guides d’ondes avec les dispositifs actifs sur PCB. Afin d’optimiser ses performances, la technologie SIW a évolué avec l’introduction du guide d’ondes intégré au substrat rempli d’air (AFSIW en anglais). La cavité d’air à l’intérieur de l’AFSIW permet de réduire considérablement les pertes diélectriques. L’AFSIW a alors été appliquée à la conception de dispositifs passifs tels que des filtres, antennes ou déphaseurs.Ces dispositifs sont conçus sur un plan unique et leurs interconnexions pour concevoir un système, tel qu’un émetteur ou récepteur radiofréquence (RF) nécessitant l’association de composants, se fait également sur le même plan. Toutefois, la structure multicouche de l’AFSIW offre de nouvelles possibilités de conceptions en utilisant ses couches inférieure et supérieure. Les composants peuvent être empilés et connectés par des transitions verticales. Le travail de cette thèse exploite la structure multicouche de l’AFSIW pour « verticaliser » un système. L’exploitation des couches inférieure et supérieure est étudiée d’une part pour la connexion de composants et d’autre part pour leur conception individuelle.Pour la connexion de composants, la plupart des transitions entre SIW, AFSIW et lignes micro ruban sont réalisées sur le même plan mais cela augmente considérablement la longueur des circuits. Au contraire, la transition entre la cavité de l’AFSIW et la ligne micro ruban proposée dans cette thèse peut être utilisée pour superposer des composants passifs et actifs sur le plan vertical en utilisant le substrat de la couche supérieure de l’AFSIW pour réduire le volume occupé.Pour la conception de composants, les couches inférieure et supérieure de l’AFSIW sont utiles pour réaliser des composants multi-cavités comme des filtres d’ordre élevé. Le couplage inter cavité d’un filtre se faisant classiquement sur le même plan, l’ordre du filtre augmentant, sa longueur augmente aussi. La transition entre cavités empilées proposé dans cette thèse offre une autre possibilité pour la conception de tels composants quand l’espace horizontal alloué serait insuffisant.L’objectif global de cette thèse est de fournir une nouvelle possibilité pour l’organisation spatiale d’un émetteur-récepteur RF. Afin de fournir une preuve de concept, la conception d’une antenne est aussi proposée permettant d’aboutir à un système comprenant l’ensemble : antenne, filtre et amplificateur. Chaque composant et cavités résonantes du filtre sont situés sur des couches différentes. Comparés à l’état de l’art où les composants sont connectés sur un même plan horizontal, les résultats obtenus démontrent la possibilité de connecter verticalement des composants. Ces deux approches de connexion de composants (exploitant le plan horizontal et vertical) offrent plus de liberté pour une utilisation optimale de l’espace 3D, particulièrement critique pour les communications spatiales en raison des contraintes sur le volume occupé dans les satellites
Waveguide technology and printed circuit board (PCB) technology are two milestones in the engineering history of microwave technology. Waveguides are at the origin of different types of passive devices such as antennas or filters while PCB technology has made it possible to integrate today's active components such as amplifiers or mixers on very small volumes. Passive components based on waveguide technology have advantages such as low insertion losses, high power handling capability and auto-blind. Substrate-integrated waveguide (SIW) technology proposed in the early 2000s reduced the size of volume waveguides by combining two technologies: metallic waveguides and PCBs. It allows for relatively low insertion losses, auto-blind and small dimensions. The introduction of SIW technology simplifies the integration of passive waveguide-based devices with active PCB-based devices. To further optimize its performance, SIW technology has evolved with the introduction in 2014 of the air-filled substrate integrated waveguide (AFSIW). The cavity placed inside the AFSIW significantly reduces dielectric losses. Since 2014, this technology has been applied to the design of various passive devices such as filters, antennas or phase shifters.These devices are individually designed on a single plane and their connections to each other to design a system, such as a radio frequency transmitter or receiver which requires the association of several components, is also done on the same plane. However, the multilayer structure of AFSIW offers new possibilities for designing these systems using its lower and upper layers. Components can be stacked and connected using vertical transitions. The work of this thesis exploits the multilayer structure of AFSIW to “verticalize” a system. The use of the lower and upper layers is studied on the one hand for the connection of the different components of a system and on the other hand for the design of components individually.For connecting different components, most of the transitions between SIW, AFSIW and various microstrip lines are made on the same plane but this significantly increases the circuit length. On the contrary, the transition between the AFSIW cavity and the micro strip line proposed in this thesis can be used to achieve the superposition of passive and active components on the vertical plane using the substrate of the upper layer of the AFSIW allowing to reduce the occupied volume.For designing individual components, the bottom and top layers of AFSIW are useful for making multi-cavity components such as high-order filters. The coupling between each cavity of a filter classically taking place on the same plane, as the order of the filter increases, its length also increases. The transition between stacked cavities proposed in this thesis offers another possibility for the design of such components in the case where the allocated horizontal space is insufficient.The overall objective of this thesis is to provide a new possibility for the spatial organization of a radio frequency transceiver. In order to provide a proof of concept, the design of an antenna is also proposed in this thesis leading to a system comprising the assembly: antenna, filter and amplifier. Each component is located on a different layer and the filter's resonant cavities are also positioned on different layers. Compared to the state of the art where the components are connected on the same horizontal plane, the results obtained demonstrate the possibility of connecting components vertically. These two approaches to connecting components (exploiting both the horizontal and vertical plane) thus offer more degrees of freedom for optimal use of 3D space, which is particularly critical for spatial communications due to occupied volume constraints at satellite level

A light flapped over the scene, as if reflected from phosphorescent wings crossing the sky, and a rumble filled the air. It was the first move of the approaching storm. The second peal was noisy, with comparatively little visible lightning. Gabriel saw a candle shining...

Abstract There are times when nature appears to revel in chaos and destruction. Breaking abruptly into the reassuring rhythm of quiet days and peaceful nights, a summer storm can suddenly materialize out of a blue and tranquil sky, shattering it like a fine crystal bowl into a thousand shards. Last summer I saw such a storm descend on gentle Ohio countryside. It was late afternoon; the sun, low in the sky, had been flooding the fields with warm evening light, gilding the little pond with its soft fringe of bull­rushes and willow trees. All at once dark cumulus clouds ap­peared on the western horizon, blocking out the light; the storm descended with an earth-shaking clap of thunder and swiftly turned the landscape into a torn and turbulent scene. Lightning rent open the boiling sky; the air was filled with flying leaves and branches. Sheets of raindrops, driven by wind gusts, fell like daggers on the field of ripening wheat which just a little while before had been rippling beneath the caress of a summer breeze. Clouds of thistledown, torn from the plants, were plas­tered in gray lumps against the treetrunks and fence posts and windowpanes.

Abstract Six-Year-Old Adam Winthrop was entranced with the new world in which he found himself following his father ‘s move to Groton, Suffolk, in 1554. The air was free of the coal-smoke miasma of London but filled with the smells of the open fields of the countryside. Cattle and sheep grazed along the local streams, and hares were a common sight. The sounds also differed from those of Cornhill, but, more important, sounds in the country- side were distinct, striking against a general quietness as opposed to the backdrop of constant noise that characterized the urban soundscape. Walking the local lanes, Adam and his brother and sisters could hear the rustling of leaves as the wind blew through the trees, the chirping of birds, the gurgle of brooks. Birds in the trees, frogs in ponds, dogs barking on nearby farms, and the grunts of pigs, lowing of cattle, and neighing of horses all put their stamp on life in Groton. Mixed with these, of course, were some familiar sounds, such as the peal of church bells marking the time, calling to worship, tolling the passing of a neighbor. Men in the fields talked and argued, shouted and sang.

I wanted to see the source of what we in the West call the Ganges. Here in South Asia people call it Mother Ganga, Gangaji, the Great Ganga. At the edge of the icy river that flows from the Gangotri glacier I scooped Gangajal—Ganges water—into plastic soft drink bottles. I planned to take some of this water to friends in Kathmandu, practicing Hindus for whom the drops of glacial melt would have spiritual meaning. Along with its tremendous religious and ritual value, the water of the Ganga has been shown to be both antimicrobial and richer in oxygen than that of other rivers. Revered beyond all others, this river is now abused in equal measure: harnessed for hydropower near its holy mountain source, polluted with every imaginable waste as it runs its course for more than 1,500 miles across the widest part of the Indian subcontinent. One of the Ganga’s main and equally sacred tributaries, the Yamuna, flows through Delhi. Delhi, a city of more than fifteen million, owes its existence to this river, which is now dead at its doorstep. Industrial effluents pour in upriver, then Delhi adds its sewage. During my first trip to Delhi in January 2007, I went down to the edge of the Yamuna. I wanted to see just how bad the river’s reputed pollution might be. First I saw the barren ground along the riverside, strewn with rubble from the construction of a nearby bridge. There was little to tell me that this area was also the site of regular religious practice where people come to do puja, take a little of the water to splash on their heads, throw some flowers into the river. Bunching up in the eddies under the bridge pylons were stray bits of colored plastic and plastic shopping bags bloated with garbage, floating like sagging baloons half filled with air. They mingled with broken yellow marigolds scattered in the water and bright red flowers set afloat in little cups by those who had come to worship by the river.