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Synthesis of Planar Microwave Circuits based on Metamaterial Concepts through Aggressive Space MappingRodríguez Pérez, Ana María 30 March 2015 (has links)
RF and microwave applications represent one of the fastest-growing segments of
the high performance electronics market, where ongoing innovation is critical.
Manufacturers compete intensively to meet market needs with reduced cost,
size, weight and many other performance criteria demands. Under this scenario,
transmission lines based on metamaterial concepts can be considered a very
interesting alternative to the conventional transmission lines. They are more
compact (compatible with planar manufacturing processes) and present higher
degrees of design flexibility. Furthermore, metamaterial transmission lines can
also provide many other unique properties not achievable with ordinary
transmission lines, such as dispersion or impedance engineering. Nevertheless,
the impact in the industry is still not relevant, mostly due to the complexity of
the related synthesis and design procedures. These procedures are mainly based
on the engineer’s experience, with the help of costly full-wave electromagnetic
(EM) simulators and parameter extraction methods.
The aim of this thesis is to contribute to simplify and speed up the synthesis
and design procedures of artificial transmission lines. In particular, the lines
obtained by periodically loading a conventional transmission line with
electrically small resonators, such as split ring resonators (SSRs) or its
complementary particle (CSRR). The design procedure is automated by using
Space Mapping techniques. In contrast to other alternative methods, real
synthesis is found from the circuit schematic (that provides a given target
response) and without need of human intervention. Some efforts to make the
method practical and useful have been carried out. Given a certain target
response, it is determined whether it can be physically implemented with a
chosen technology, and hence proceeding next to find the synthesis, or not. For
this purpose, a two-step Aggressive Space Mapping approach is successfully
proposed.
In contrast to other methods, the real synthesis is found from certain target
circuit values (corresponding to the equivalent circuit model that characterizes
the structure to be synthesized). Different efforts have been carried out in order
to implement a useful and practical method. Some of them were focused to determine if, given certain circuit parameters (which determine the target
response) and certain given technology specifications (permittivity and height of
the substrate, technology limits), that response is physically realizable
(convergence region). This technique was successfully formulated and it is
known as “Two-Step Aggressive Space Mapping Approach”.
In this work, the latest improvements made till date, from the synthesis of
basic unit cells until different applications and kinds of metamaterial-based
circuits, are presented. The results are promising and prove the validity of the
method, as well as its potential application to other basic cells and more complex
designs. The general knowledge gained from these cases of study can be
considered a good base for a coming implementation in commercial software
tools, which can help to improve its competitiveness in markets, and also
contribute to a more general use of this technology. / Rodríguez Pérez, AM. (2014). Synthesis of Planar Microwave Circuits based on Metamaterial Concepts through Aggressive Space Mapping [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48465 / TESIS
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Antenna Performance Control using Metamaterials / Contrôle des performances des antennes par les métamatériauxAyad, Houssam 02 June 2012 (has links)
Le travail de cette thèse est en rapport avec les métamatériaux et ses applications. Tout d’abord, un état de l’art est dressé en présentant leur évolution depuis leur apparition en 19ème siècle jusqu’au nos jours. Les notions sur les milieux chirale, bi-anisotrope, cristaux photoniques et quelques applications dans ces milieux sont données. Ensuite, nous présentons les équations classiques de Maxwell dans les milieux complexes. L’effet bi-anisotrope dans les métamatériaux est ensuite validé par l’extraction des paramètres caractéristiques du matériau main gauche (LHM). La validation a été faite en utilisant deux types différents du résonateur avec inclusion (SRR). Les métamatériaux sont également étudiés comme des cristaux photoniques quand les dimensions utilisées sont de l’ordre de la longueur d’onde correspondant.De plus, les résonateurs SRR et multi-SRR sont analysés du point de vue analytique et électromagnétique afin d’extraire leur fréquence de résonance. Par conséquent, ces composants peuvent être introduits dans différents types de conception; La surface conductrice magnétique artificielle (AMC) illustre un cas explicite et efficace de ces derniers. Une antenne dipôle, placée sur cette surface à la place d’un plan de masse conventionnel, a été étudiée comme une application des métamatériaux. Les résultats relatifs sur la directivité, le gain et le coefficient de réflexion montrent une nette amélioration. Une antenne multi-bandes, comme une autre application des métamatériaux, a également été conçue et simulée. Le résonateur SRR est inséré dans l’antenne de départ afin de créer une autre résonance, et par conséquent une autre bande est ainsi créée. / The work in this thesis deals with metamaterials, its components and applications. A historical overview about these materials, features and researches in the domain are presented. Chiral media, binaisotropic materials and photonic crystals are also studied in order to visualize physics behind metamaterials.Electromagnetic properties in complex media are widely investigated. Starting from Maxwell’s equations, bi-anisotropic materials and their effect are deeply analyzed whereas two types of Split Ring Resonator (SRR) are treated to determine constitutive parameters of Left Handed Materials (LHM). The metamaterials are also studied as photonic crystals since the effective medium approach is not applicable when the dimensions of the inclusions tend to the operating wavelength.Moreover, SRRs and Multi SRRs are synthesized analytically and electromagnetically in order to extract their resonant frequencies. Consequently, these components could be introduced in any design; Artificial Magnetic Conductor (AMC) surface is an efficient case. Thus, a low profile antenna positioned over such surface is examined as an application of metamaterials. The results of directivity, gain and reflection coefficient are of great importance and affirm the employing of metamaterials in such applications. A dual band PCB antenna, as another application of metamaterials, is designed and simulated. The SRR element studied in the previous chapters is used as the trap which inserted in the arm of the antenna in order to create another resonance, and consequently another band is created.
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