Yes / A tunable band-notch printed monopole antenna is presented, exhibiting a wide impedance bandwidth from 1.5 to 5.5 GHz with good impedance matching (VSWR ≤ 2) and a tunable rejected frequency band from 2.38 to 3.87 GHz. The band-notching is achieved by adding an inner chorded crescent element within a driven element of a similar shape. By varying the value of the varactor which is placed between the inner and outer arcs, the desired variable rejected can be obtained. Simulated and measured results show wide impedance bandwidth with a tunable band notch, stable radiation patterns, and consistent nearly constant gain. The antenna is suitable for mobile and portable applications.

No description available.

No / This work presents a novel broadband monopole antenna for digital video broadcastingterrestrial (DVB-T) application. The proposed antenna consists of a grating patch and a concave rectangular ground plane with defected ground plane, and the Multiple Split-Ring Resonator (MSRR). The added part in the ground plane and the meta-material are used to enable the antenna height reduction for fixed ranges of operating frequency. The antenna can operate from 468 MHz to 894 MHz frequency range corresponding to 62.5% of impedance bandwidth for |S11|<-7.5 dB. Details of the proposed antenna designs and experimental results of the constructed prototypes are presented and discussed.

Yes / Four versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48 % (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2GHz) and X-Band systems (10GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tuneable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2GHz to 5.1GHz and from 7.25GHz up to 9.9GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results. / This work is carried out under the grant of the Fundacão para a Ciência e a Tecnologia (FCT - Portugal), with the reference number: SFRH/BPD/95110/2013.

Novel antennas attractive to fit in the internal space of a PDA (Personal Digital Assistant) for WLAN (Wireless Local Area Network) operations are presented in this dissertation. The proposed antennas have in common good impedance bandwidth (defined by 10 dB return loss), covering the dual-band WLAN operation in the 2.4/5.2 GHz bands. Two novel designs of foam-base surface-mount antennas are proposed in Chapters 2 and 3. Surface-mountable antennas, compared with ceramic antennas, are generally low cost in fabrication and rigid in nature. Low-profile and good dual-band operation of the proposed surface-mountable antennas can be observed in Chapters 2 and 3, and in addition, a few present-day WLAN bands at 5 GHz are covered in the operating bandwidths of the proposed foam-base surface-mountable shorted monopole antenna, shown in Chapter 3. Finally, in Chapter 4, a novel planar helical antenna printed on both surfaces of a dielectric substrate is demonstrated. This patent-pending helical antenna is very suitable to print and integrate on a circuit board of a PDA device for 2.4/5.2 GHz WLAN operation.

Après une introduction générale et une revue de littérature (chapitre 1), l’apport de cette thèse est de déterminer le rôle de la demande dans l’émergence d’un stock de marchandises invendues. Les préférences des consommateurs sont modifiées puisqu’elles prennent en compte non seulement les quantités consommées mais également celles étalées. Le cadre d’analyse de cette thèse est celui d’un jeu stratégique à deux joueurs en univers certain, avec prix flexibles et information parfaite. Deux types de consommateurs sont considérés : certains apprécient l’étalage et d’autres non. Un monopole modifié choisit à la fois le prix et l’étalage. Les propriétés de l’équilibre de Nash en stratégies pures sont étudiées. Le chapitre 2 présente un modèle de détermination du mark-up optimal pour n’importe quelle valeur de l’élasticité prix de la demande (contrairement à l’indice de Lerner qui peut être utilisé uniquement pour les biens élastiques). Le chapitre 3, étend le second, en déterminant le coefficient multiplicateur optimal en présence de stocks d’invendus. Il permet de définir la solde optimale. Le quatrième et dernier chapitre détermine les conditions sur les fonctions d’utilité qui permettent de générer un stock d’invendus à l’équilibre de Nash en stratégies pures. Les modèles développés sont élargis au cas où un planificateur social intervient dont l’objectif est de maximiser le bien-être de l’économie. / After a general introduction and a survey of literature, the contribution of this thesis is to determine the role of the demand in the emergence of unsold stock of goods based on consumer’s preferences argument. Throughout the thesis, we consider a strategic game with two players under perfect information, certainty and price flexibility. Consumers are of two types: with appreciation to the display and without. A modified monopoly chooses both the price and the display. Chapter 2 presents an original model to determine the optimal markup for both elastic and inelastic goods (unlike the Lerner index that is used only for elastic goods). Chapter 3 is an extension of the previous one. It is about the determination of an optimal markup with the presence of unsold stock of goods. The fourth and final Chapter analyzes under which conditions an unsold stock of goods is supported by a pure strategy Nash equilibrium. All the models developed present a welfare analysis.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-11-06T20:00:02Z No. of bitstreams: 1 Marcos Lima Dias.pdf: 1365744 bytes, checksum: 2aa8dc442d4e20438c570810fb9d2ab8 (MD5) / Made available in DSpace on 2017-11-06T20:00:02Z (GMT). No. of bitstreams: 1 Marcos Lima Dias.pdf: 1365744 bytes, checksum: 2aa8dc442d4e20438c570810fb9d2ab8 (MD5) Previous issue date: 2017-04-13 / CAPES / The theoretical study about the existence of magnetic monopole has begun by P. A. M. Dirac in 1931 and its main consequence has been the possibility of explaining the quantization of the electric charge. In Grand Uni cation Theories (GUT's), the magnetic monopole may appear as a topological defect by spontaneous symmetry break, in a process known as Higgs mechanism. The GUT's also predict the existence of a topological soliton which has both magnetic and electric charges: the so-called dyon. Theoretically, these particles are predicted very massive and abundant in the Universe. There are particular cases of monopole and dyon, called BPS's states, which have the smallest possible mass values, besides analytical solutions. In this work, we present some basic ideas about topology and homotopy; we describe the main points that have led to the development of the theoretical study of monopole and dyon both as topological solitons; and nally we investigate the e ects of the Lorentz-violating CPTeven terms in the Gauge (in particular, non birefringent one) and Higgs sectors on the BPS's states of the 't Hooft-Polyakov magnetic monopole and of the Julia-Zee dyon, both given in the Georgi-Glashow SO(3) model. / O estudo teórico a respeito da existência do monopolo magnético foi iniciado por P. A. M. Dirac em 1931 e teve como principal consequência a possibilidade de explicar a quantização da carga elétrica. Em Teorias de Grande Unificação (GUT's), o monopolo magnético pode surgir como um defeito topológico por meio da quebra espontânea de simetria, em um processo conhecido como mecanismo de Higgs. As GUT's preveem também a existência de um sóliton topológico que possui tanto carga magnética quanto elétrica: o chamado dyon. Teoricamente, essas partículas se apresentam muito massivas e abundantes no Universo. Hé casos particulares do monopolo e do dyon, denominados estados BPS's, que têm os menores valores possíveis de massa, cujas soluções são analíticas. Neste trabalho, apresentamos algumas ideias básicas acerca de topologia e homotopia; descrevemos os principais pontos que levaram ao desenvolvimento do estudo teórico do monopolo e do dyon como sólitons topológicos; e investigamos finalmente os efeitos dos termos CPTpares de violação da simetria de Lorentz nos setores de Gauge (em especial, n~ao birrefrigente) e de Higgs sobre os estados BPS's do monopolo magnético de't Hooft-Polyakov e do dyon de Julia-Zee, ambos dados no modelo SO (3) de Georgi-Glashow.

It is well-known that in 2 + 1 dimensions the flux attachment transmutes the statistics of a particle.The aim of this master thesis is to study the dualities between bosons and fermions induced by Abeliantopological gauge fields in 2 + 1 dimensions. Chapter 1 and 2 are reviews of known results about thepath integral quantization of Chern-Simons theory and the regularization of the fermionic path integral.In the following chapters, we will derive the statistical transmutation and various Abelian dualities in2 + 1 dimensions.

Switched and adaptive parasitic monopole array radiating structures are investigated. Antenna design is orientated toward increasing practicability for implementation in terrestrial wireless communication systems. A number of antennas are designed with the aid of optimization and commercial simulation software. Simulation procedure was verified with the experimental manufacture and measurement of the arrays. The antennas presented in this thesis comprise an active monopole surrounded by a ring of parasitic monopoles. Parasitic radiators are constructed with static loading to enable simple experimental realization. Beam positions of an electrically steered equivalent antenna are thus simulated. Antenna symmetry ensures the beam can be reproduced throughout the azimuth. Complex antenna geometries require antenna design through optimization. A genetic algorithm is employed with HFSS and NEC for electromagnetic analysis. The robust optimization method couples with simulation software flexibility to provide an effective design tool for arbitrary structures. The genetic algorithm is employed strictly for design and not complete structural optimization. Dual band, five and six element switched parasitic antennas are presented. Lumped elemental loading along the radiators provide resonance and directed radiation at two GSM frequencies. Load value, radiator dimension and spacing are incorporated as design parameters. Experimentally built, 10dB return loss bandwidths of 17.2% and 9.6% and front to back ratios of 12.6dB and 8.4dB at 900MHz and 1900MHz respectively are measured. To reduce the ground requirements of monopole arrays, a skirted ground structure for switched parasitic antennas is analyzed. A six element switched parasitic monopole array with conductive ground skirt exhibits a front to back ratio of 10.7dB and main lobe gain of 6.4dBi at 1.575GHz. Radiation is not elevated despite lateral ground terminating at the parasitic elements. Skirt height is observed to linearly control radiation elevation, depressing the principal lobe through 40 degrees from 23 degrees above the horizontal. The Electronically Steerable Passive Array Radiator or ESPAR antenna is an adaptive parasitic monopole array. An ESPAR radiating structure incorporating a conductive ground skirt is designed for operation at 2.4GHz. Utility is confirmed with a frequency sensitivity analysis showing consistent electrical characteristics over an 8.1% bandwidth. The antenna design is improved with optimization to reduce average principal lobe elevation from 25 degrees to 9.7 degrees.

<p>The overall goal of the thesis is to establish detailed comparisons among different well-known models of excitations in their application on Microstrip-like Monopoles. Comparisons are made over the input impedances predicted by these excitations. In this way, the Galerkin’s version of the Method of Moment is applied and rooftops functions are chosen as our basis/weighting functions. Different excitation models have their influence over the excitation vector and a unique MoM matrix is used to give input impedances. We shall elicit the effects of several parameters over relative input self/mutual impedances derived from these excitation models and finally make conclusions about their differences in anticipating the input Resistance, input Reactance and also resonance frequencies.</p>