Notice bibliographique
Résumé
This PhD dissertation explores novel electromagnetic applications using negative-group-delay (NGD) and non-Foster structures and establishes an intimate connection between these two phenomena. As a result, novel implementations of non-Foster reactive elements using NGD networks are proposed. To this end, NGD and non-Foster structures are investigated separately in Chapters 1 and 2 and related corresponding applications are explored. Then, a two-way link between these two phenomena is proposed, analytically demonstrated and experimentally verified in Chapters 3. This link provides a novel perspective in the realization of non-Foster reactive elements, leading to new designs that are well-behaved and more predictable in terms of stability and operation than traditional designs. Particularly, a class of non-Foster elements, called unilateral reactive non-Foster elements, is presented where losses are compensated using regular unilateral amplifiers. This type of non-Foster element is implemented by cascading an amplifier and a passive load, operating as a NGD network, and provides a stable operation for new applications.\nIn Chapters 4, in preparation for the following chapter where a novel application of reactive non-Foster elements in embedded-matching-network applications is introduced, a frequency-reconfigurable antenna is presented which provides an excellent compromise among size, frequency tuning range and count of tuning elements. In Chapters 5, a design procedure for replacing the tuning element with a circuit, generating a non-Foster reactance, is presented. This embedded circuit creates a wide matching bandwidth at the antenna terminals.\nIn Chapters 6, passive and active approaches for eliminating beam-squinting in linear series-fed arrays are investigated and experimentally verified. The passive approaches are designed based on the parameters of the branches connecting the feedline to the antenna elements, whereas the active approach works on the parameters of the feedline. The active approach employs unilateral reactive non-Foster elements, synthesized by NGD networks, in the feedline.\nChapters 7 presents the properties of positive-index/negative-index coupled-line structures, where simplified relations describing these structures in the complex-mode band are derived. Based on these relations, the properties of these structures are discussed. By employing these properties, two applications, namely a NGD structure and a novel traveling-wave resonator, are demonstrated. \nAlthough this dissertation focuses on non-Foster and negative-group-delay structures, extra work is described in parts of the thesis to explore relevant structures and to propose novel applications. In this regard, in Chapters 4, before presenting the antenna with an embedded matching network and in a relevant application, a frequency-reconfigurable antenna is presented. Moreover, in Chapters 5, passive approaches for squint-free beamforming in series-fed arrays are explored and implemented. Further, in Chapters 6, the applications of positive-index/negative-index guides in constructing a novel type of resonator with multiple resonant frequencies, in a certain bandwidth, are investigated.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,005 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».