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Radiation Pattern Reconfigurable Horn Antenna Based on Parasitic Layer ConceptTanagardi, Mehmet 01 August 2019 (has links)
In recent years, multi-functional reconfigurable antennas (MRA) has attracted much attention in wireless communication. The reconfigurable antenna can adapt itself with changing system conditions, and it can provide different multi-functionalities which can give better system performances. Instead of using multiple antennas, a single reconfigurable antenna can provide the same performance and occupy less space. By using the parasitic layer technique, an antenna can be turned into a reconfigurable antenna. The main objective of this thesis is to study radiation pattern reconfiguration of the horn antenna by using the parasitic layer concept. The MRA consists of a single horn, dielectric loaded truncated pyramid (DLTP), and the parasitic layer. The antenna that is chosen in this thesis is the horn antenna because it provides high directivity. DLTP is used for magnification purpose. The results show that three modes of operations that provide better performances compared to the single horn antenna are achieved.
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Power-line sparking noise characterisation in the SKA environmentLangat, Philip Kibet 12 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The Square Kilometre Array (SKA) and its demonstrator MeerKAT are being designed to operate over
a wide frequency range and are expected to achieve greater sensitivity and resolution than existing
telescopes. The radio astronomy community is well aware of the negative impact that radio frequency
interference (RFI) has on observations in the proposed frequency band. This is because weak radio
signals such as those from pulsars and distant galaxies are difficult to detect on their own. The presence
of RFI sources in the telescope’s operating area can severely corrupt observation data, leading to
inaccurate or misleading results.
Power-line interference and radiation from electric fences are examples of RFI sources. Mitigation
techniques for these interference sources in the SKA system’s electromagnetic environment are
essential to ensure the success of this project. These techniques can be achieved with appropriate
understanding of the characteristics of the noise sources. Overhead power-line interference is known to
be caused mainly by corona and gap-type (commonly known as sparking noise) discharges. Sparking
noise is the dominant interference for the SKA. It is mainly encountered on wooden pole lines, which
are usually distribution lines operated at up to 66 kV AC in the South African network. At this voltage
level, the voltage gradients on the lines are insufficient to generate conductor corona. The power
requirements for SKA precursors will be below this voltage level.
The aim of the research in this dissertation is to evaluate the power line sparking characteristics
through measurements and simulation of line radiation and propagation characteristics. An artificially
made sparking noise generator, which is mounted on a power line, is used as noise source and the
radiation characteristics are measured. Measurements were carried out in different environments,
which included a high-voltage laboratory (HV-Lab), a 40m test-line, and another 22-kV test line of
approximately 1.5 km. The key sparking noise parameters of interest were the temporal and spectral
characteristics. The time domain features considered were the pulse shape and the repetition rate. The
lateral, longitudinal and height attenuation profiles were also quantified. Since sparking noise current pulses are injected or induced onto power line conductors, the line will
act as an unintentional antenna. The far-field radiation characteristics of the line were evaluated
through measurements on physical scale-model structures and simulations. 1/120th and 1/200th scaled
lines, using an absorbing material and metallic ground planes, respectively, were simulated in FEKO.
The measurements of the constructed scale models were taken in the anechoic chamber. Both
measurements and simulations showed that the line exhibits an end-fire antenna pattern mode. Line
length, pulse injection point and line configuration were some of the parameters found to affect the
radiation patterns.
The findings from this study are used to determine techniques to identify the sparking noise, and locate
and correct the sources when they occur on the line hardware. Appropriate equipment is recommended
to be used for the location and correction of sparking noise. / AFRIKAANSE OPSOMMING: Die Vierkante Kilometer Reeks (SKA) en sy demonstrasie projek, die Karoo Reeks Teleskoop (KAT),
word ontwerp om oor 'n wye frekwensie-bereik te funksioneer. Beide sal na verwagting beter
sensitiwiteit en resolusie as bestaande radioteleskope he. Die radio-astronomie-gemeenskap is deeglik
bewus van die negatiewe impak wat radio-frekwensie steurnisse (RFS) op waarnemings in die
voorgestelde frekwensieband het. Die rede hiervoor is dat swak radio-seine soos die van pulsars en
verafgelee sterrestelsels inherent moeilik is om te bepaal. Die teenwoordigheid van RFS bronne in die
teleskoop se onmiddellike operasionele gebied kan waarnemings nadelig beinvloed. Dit lei uiteindelik
tot onakkurate of misleidende resultate.
Kraglyne en uitstralings van elektriese heinings is voorbeelde van RFS bronne. Metodes om die
oorsake van die steurnisse van die SKA se elektromagnetiese omgewing te verminder is noodsaaklik
om die sukses van hierdie projekt te verseker. Dit vereis egter deeglike begrip van die eienskappe van
hierdie bronne. Steurnisse as gevolg van oorhoofse kraglyne word hoofsaaklik veroorsaak deur
korona en gapingtipe ontladings (algemeen bekend as vonkontladings). Vonkontladings word hier
beskou as die belangrikste oorsaak van steurnisse vir die SKA. Dit word in die Suid-Afrikaanse
netwerk hoofsaaklik aangetref op houtpaal-installasies, wat gewoonlik bestaan uit distribusie lyne
wat tot en met 66 kV wisselstroom (WS) bedryf word. By hierdie operasionele spanning is die
spanningsgradient op die lyn onvoldoende om korona op te wek. Die kragvereistes vir die SKA se
voorafgaande projekte sal sodanig wees dat hierdie spanningsvlak nie oorskry sal word nie.
Die doel van die navorsing omskryf in hierdie proefskrif is om die eienskappe van vonkontladings
rondom kraglyne te evalueer. Dit word gedoen met behulp van metings en simulasies van
uitstralings- en voortplantingspatrone wat met 'n spesifieke lyn geassosieer kan word. 'n Kunsmatige
vonkontladingsopwekker word op 'n kraglyn geplaas en dien as bron om die uitstralingspatrone te
meet. Metings is uitgevoer in verskillende omgewings, insluitende 'n hoogspanningslaboratorium
(HV-Lab), 'n 40 m toetslyn en 'n 22 kV WS toetslyn van ongeveer 1.5 km lank. Die hoof
vonkontladings eienskappe van belang is die temporale en spektrale eienskappe. Die tydgebiedeienskappe
wat ondersoek is, is die pulsvorm asook die pulsherhalingskoers. Die laterale,
longitudinale en hoogte-attenuasie profiele word ook gekwantifiseer. Aangesien stroompulse deur vonkontladings op die kraglyn geplaas of geinduseer word, sal die lyn as
'n ongewenste antenna optree. Die ver-veld uitstralingskenmerke van die lyn is ook geëvalueer deur
gebruik te maak van fisiese skaalmodelstrukture en -simulasies. 1/120ste en 1/200ste geskaleerde
lynmodelle, wat onderskeidelik 'n absorberende- en metaalgrondvlak bevat, was gebruik om 'n 3
spanlengte kraglyn te simuleer met behulp van FEKO. Metings van die fisiese skaalmodel strukture is
in 'n anegoise kamer geneem. Beide die metings en die simulasies toon dat die lyn 'n endpunt
uitstralingspatroon het. Lynlengte, die opwekkingsposisie van die stroompuls en die lynkonfigurasie
is 'n paar van die parameters wat die uitstralingpatroon beïnvloed, soos in die navorsing aangedui.
Die bevindinge van hierdie studie word gebruik om steurnisse as gevolg van vonkontladings op die
kraglyn te identifiseer, op te spoor en uiteindelik reg te stel. Toepaslike toerusting word voorgestel
wat gebruik kan word vir die identifisering en opsporing van vonkontladings.
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Design and implementation of band rejected antennas using adaptive surface meshing and genetic algorithms methods : simulation and measurement of microstrip antennas with the ability of harmonic rejection for wireless and mobile applications including the antenna design optimisation using genetic algorithmsBinmelha, Mohammed Saeed January 2013 (has links)
With the advances in wireless communication systems, antennas with different shapes and design have achieved great demand and are desirable for many uses such as personal communication systems, and other applications involving wireless communication. This has resulted in different shapes and types of antenna design in order to achieve different antenna characteristic. One attractive approach to the design of antennas is to suppress or attenuate harmonic contents due to the non-linear operation of the Radio Frequency (RF) front end. The objectives of this work were to investigate, design and implement antennas for harmonic suppression with the aid of a genetic algorithm (GA). Several microstrip patch antennas were designed to operate at frequencies 1.0, 1.8 and 2.4 GHz respectively. The microstrip patch antenna with stub tuned microstrip lines was also employed at 1.0 and 1.8 GHz to meet the design objectives. A new sensing patch technique is introduced and applied in order to find the accepted power at harmonic frequencies. The evaluation of the measured power accepted at the antenna feed port was done using an electromagnetic (EM) simulator, Ansoft Designer, in terms of current distribution. A two sensors method is presented on one antenna prototype to estimate the accepted power at three frequencies. The computational method is based on an integral equation solver using adaptive surface meshing driven by a genetic algorithm. Several examples are demonstrated, including design of coaxially-fed, air-dielectric patch antennas implanted with shorting and folded walls. The characteristics of the antennas in terms of the impedance responses and far field radiation patterns are discussed. The results in terms of the radiation performance are addressed, and compared to measurements. The presented results of these antennas show a good impedance matching at the fundamental frequency with good suppression achieved at the second and third harmonic frequencies.
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Characteristics of the log periodic dipole arrayOnwuegbuna, Leonard Ikemefuna 28 February 2007 (has links)
Student Number : 9713144D -
MSc Dissertation -
School of Electrical Engineering -
Faculty of Engineering and the Built Environment / The performance of the Log Periodic dipole array antenna has been characterized,
in the form of parametric curves available in most antenna design handbooks and
other relevant literature. These characteristic curves are often limiting in scope,
as for instance they do not contain parametric curves giving the relationship
between the boom-length 'L' and the number of dipole element 'N' for any given
bandwidth, even when it is known that these two parameters are the main cost
determinants of a LPDA Antenna. The concept of convergence is introduced to
aid cost optimization of the LPDA Antenna in terms of number of dipole element
'N'. Although 'N' is used as the minimization criterion, the criteria for establishing
convergence encompass all the main electrical characteristics of the LPDA
Antenna, such as VSWR, gain and radiation patterns. Lastly, the effects of boomimpedance
'Zo' and length to diameter ration 'Ln/Dn', on the performance
characteristics of the LPDA Antenna was investigated with the view to
determining if neglecting the effects of these two parameters were responsible for
the disparity in the directive gain values obtained by R. L Carrel compared to
those obtained by later researchers. The investigation indicates that if an LPDA
Antenna is converged, then the effects of Zo and Ln/Dn ratio though significant
can not alone account for the fairly large disparity in the gain values.
In other to perform these investigations, a modern scientific tool in the form of
numerical modeling by method of moments based, Super Numerical
electromagnetic code version2 was utilized. The numerical modeling tool was
first validated by agreement between measured values and the values as predicted
by the modeling tool. Next, simulation of the performance of LPDA antennas
under variations of their number of elements was done. Thereafter, the means and
standard deviations of the gain were extracted from the simulated numerical
models. Trends in the pattern of variation of the means and standard deviations of
the gain are used as the basis for deciding the value of number of element at
which the antenna can yield acceptable performance (convergence criteria). These
are presented as convergence curves, which gives for any given boom-length and operating bandwidth, the minimum number of elements required for the antenna
to yield acceptable performance.
Finally, the effect of length to diameter ratio and boom-impedance on the gain of
optimized LPDA antennas are presented as parametric curves.
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Dielectric Resonator Antennas (DRA) for satellite and body area network applicationsAlam, Muhammad Faiz, Alam, Muhammad Faiz 02 July 2012 (has links) (PDF)
Technologies such as direct broad cast satellite system (DBSS), Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite communications , global positioning system (GPS), high accuracy airborne navigation system and a large variety of radar systems demand for high level of antenna performance. Similar is the requirement for upcoming land based wireless systems such as cellular and indoor communication systems that is needed some more specific and additional features added to the antenna to compensate for the deficiencies encountered in system's performance. Though metallic antennas are capable enough to fulfil all the operational requirements, however at very high frequencies and under hostile temperature conditions they are constrained to face certain limitations. To avoid these constraints the performance of Dielectric Resonator Antennas (DRAs) is evaluated and their new applications are proposed. In the thesis, two types of antenna applications are sought :-First is for tracking and satellite applications that needs a larger aperture coverage in elevation plane. This coverage is realized with a good CP purity by proposing two ports dual linearly polarized DRA working at X-band. The DRA is excited by two orthogonal H-shaped aperture slots yielding two orthogonal polarizations in the broadside direction. A common impedance bandwidth of 5.9% and input port isolation of -35 dB are obtained. The broadside radiation patterns are found to be highly symmetric and stable with cross polarization levels -15dB or better over the entire matching frequency band. The maximum measured gain is found to be 2.5dBi at 8.4 GHz.- The 2nd type of antenna is a dual pattern diversity antenna to be used in the Body Area Network (BAN) context. This antenna combines a slot loop and DRA yielding broadside and end-fire radiation patterns respectively. Based upon the feeding techniques, the DG antenna is further divided into two categories one with planar feeds and the other with non-planar feeds (slot loop excited by planar CPW but DRA excited by vertical monopole) .Both types are successfully designed and measured upon body when configured into different propagation scenarios. The non-planar feeds antenna allows wider common impedance bandwidths than the planar feeds (4.95% vs 1.5%).In both cases, a maximum value of DG=9.5dB was achieved when diversity performance tests were carried out in rich fading environments. This value is close to the one (10 dB) theoretically reached in a pure Rayleigh environment and was obtained with efficiencies of 70% and 85% for the slot loop and the DRA respectively. Therefore, we conclude that these antennas could be used on the shoulders or the chest of professional clothes (firemen, policemen, soldier) where full planar integration is not a key issue but where the communication must be efficient in harsh environments and for various gestures, positions and scenarios
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[en] ANALYSIS AND SYNTHESIS OF REFLECTARRAYS FOR SPACE APPLICATIONS / [pt] ANÁLISE E SÍNTESE DE REDES REFLETORAS PARA APLICAÇÕES ESPACIAISEDSON RODRIGO SCHLOSSER 21 August 2020 (has links)
[pt] Neste trabalho é apresentada a análise e síntese de redes refletoras para aplicações espaciais. Redes refletoras são abordadas para expor de forma sucinta suas aplicações, geometrias, métodos de análise e de síntese de diagramas de irradiação. O método do circuito equivalente é utilizado para a formulação da função diádica de Green, possibilitando estabelecer relações entre os campos eletromagnéticos e as densidades superficiais de corrente elétrica em meios estratificados e constituídos por diversas metalizações. Validações numéricas são realizadas através da determinação das constantes de propagação em estruturas slab e guia de onda parcialmente preenchido, formadas por paredes metálicas com condutividade infinita. Análises de redes refletoras com poucos elementos são realizadas empregando-se o método dos momentos para calcular numericamente as densidades superficiais de corrente elétrica que fluem sobre os patches. Adicionalmente, propõe-se a aplicação de uma função base de domínio completo com condição de borda segmentada para modelar o comportamento impulsivo da densidade de corrente nas bordas dos espalhadores. Diferentes curvas de fase são obtidas através da técnica de variação das dimensões físicas dos espalhadores metálicos, considerando o campo elétrico total composto pelos campos espalhado, refletido e difratado, devido às posições espaciais dos patches. Softwares comerciais são utilizados nas verificações dos resultados obtidos. Por fim, o conceito de defasagem progressiva e o método de enxame de partículas foram aplicados para se determinar a fase desejada em cada célula. Assim, as curvas de fase são interpoladas e utilizadas para projetar as dimensões dos elementos impressos e garantir a distribuição de fase calculada sobre a superfície da rede refletora, de forma a reproduzir os diagramas desejados. / [en] This thesis presents the analysis and synthesis of reflectarrays for space applications. A review of the state-of-the-art of reflectarrays is presented and the applications, geometries, methods of analysis and methods of synthesis are discussed. Dyadic Green s function is formulated using the equivalent circuit method to describe the relation between electromagnetic fields and electrical current densities in structures composed of stratified media and several metallizations. Slab and partially-filled waveguide formed by metallic walls with infinite conductivity are analyzed to validate the formulation. Analyses of reflectarrays with few elements are performed using the method of moments to numerically calculate the densities of electric current that flow on the patches. Additionally, entire-domain basis function with segmented edge condition to model the impulsive behavior of current density at the edges of the scatterers is proposed. Different phase curves are obtained due to the patches positions in the reflectarray using the variable size technique. Phase curves are calculated considering a total electric field composed of scattered, reflected and diffracted fields. Commercial software is used to verify the obtained results. Finally, the desired phase in each cell is determined using the progressive phase concept and the particle swarm optimisation method. The phase curves are used to design the dimensions of the printed elements, and, thus, ensure the desired phase distribution on the surface of the reflectarrays, and, consequently, the specified radiation pattern.
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Design and implementation of band rejected antennas using adaptive surface meshing and genetic algorithms methods. Simulation and measurement of microstrip antennas with the ability of harmonic rejection for wireless and mobile applications including the antenna design optimisation using genetic algorithms.Bin-Melha, Mohammed S. January 2013 (has links)
With the advances in wireless communication systems, antennas with different shapes and design have achieved great demand and are desirable for many uses such as personal communication systems, and other applications involving wireless communication. This has resulted in different shapes and types of antenna design in order to achieve different antenna characteristic. One attractive approach to the design of antennas is to suppress or attenuate harmonic contents due to the non-linear operation of the Radio Frequency (RF) front end.
The objectives of this work were to investigate, design and implement antennas for harmonic suppression with the aid of a genetic algorithm (GA). Several microstrip patch antennas were designed to operate at frequencies 1.0, 1.8 and 2.4 GHz respectively. The microstrip patch antenna with stub tuned microstrip lines was also employed at 1.0 and 1.8 GHz to meet the design objectives.
A new sensing patch technique is introduced and applied in order to find the accepted power at harmonic frequencies. The evaluation of the measured power accepted at the antenna feed port was done using an electromagnetic (EM) simulator, Ansoft Designer, in terms of current distribution. A two sensors method is presented on one antenna prototype to estimate the accepted power at three frequencies.
The computational method is based on an integral equation solver using adaptive surface meshing driven by a genetic algorithm. Several examples are demonstrated, including design of coaxially-fed, air-dielectric patch antennas implanted with shorting and folded walls. The characteristics of the antennas in terms of the impedance responses and far field radiation patterns are discussed. The results in terms of the radiation performance are addressed, and compared to measurements. The presented results of these antennas show a good impedance matching at the fundamental frequency with good suppression achieved at the second and third harmonic frequencies. / Home government
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Investigating Antenna Placement on Autonomous Mining VehicleManara, Luca January 2016 (has links)
Future mines will benefit from connected intelligent transport system technologies. Autonomous mining vehicles will improve safety and productivity while decreasing the fuel consumption. Hence, it is necessary for Scania to increase the know-how regarding the design of vehicular communication systems for the harsh mine environment. The scope of this work is to examine the requirements for the antenna placement of a future autonomous mining truck and propose suitable antenna types and positions. By using the electromagnetic simulator suite CST Microwave Studio, the research estimates the impact of a simplified autonomous mining vehicle geometry on basic antenna radiation patterns. Some simulated antenna configurations are assessed with radiation pattern measurements. In order to radiate enough power towards the area surrounding the vehicle and guarantee reliable communications, the truck requires omnidirectional antennas in centered locations, or alternatively one patch antenna for each side. The method used to solve the problem is also assessed: flexibility provided by the simulation method is emphasized, whereas some relevant limitations are discussed. Hardware requirements, availability of the models and limited results provided by the software can make the simulation phase not suitable to evaluate the antenna placement. / Framtidens gruvor kommer att gynnas av sammankopplade, intelligenta transportsystem. Autonoma gruvfordon kommer att förbättra säkerhet och produktivitet, och samtidigt minska bränslekonsumtion. Därför är det nödvändigt för Scania att öka kunskapen om design av kommunikationssystem för fordon i hård gruvmiljö. Målet för detta projekt är att undersöka kraven för antennplacering hos ett framtida autonomt gruvfordon och att ge förslag på passande antenntyper och -positioner. Det elektromagnetiska simuleringsverktyget CST Microwave Studio används för att uppskatta påverkan från en förenklad fordonsgeometri på grundläggande antennstrålningsmönster. Utvalda antennkonfigurationer utvärderas genom undersökningar av dess strålningsmönster. För att kunna stråla ut tillräcklig effekt i området kring fordonet och garantera tillförlitlig kommunikation krävs centralt placerade runtstrålande antenner, eller alternativt en patchantenn till varje sida. Problemlösningsmetoden utvärderas också: Flexibiliteten simuleringsmetoden ger betonas, medan några relevanta begränsningar diskuteras. Hårdvarukrav, tillgängligheten av modeller och begränsade resultat från mjukvaran kan bidra till att göra simuleringen olämplig för att utvärdera antennplaceringen.
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Miniaturized tunable conical helix antennaZhu, F., Ghazaany, Tahereh S., Abd-Alhameed, Raed, Jones, Steven M.R., Noras, James M., Suggett, T., Marker, S. January 2014 (has links)
No / A miniaturized conical helix antenna is presented, which displays vertical polarization with electrically small dimensions of 10mm×10mm×45mm. The resonance of the antenna is made tunable by adding a variable digital MEMS capacitor load at the bottom of the helix, giving a tuning range of 316 MHz to 400 MHz. The antenna demonstrates considerable impedance matching bandwidth and gain over the entire tuning frequency band. Most importantly, the antenna is capable of compact, flexible and easy integration into a wireless device package or for platform installation. / Datong of Seven Technology Group, for their support under the KTP project grant No. 008734.
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Dielectric Resonator Antennas (DRA) for satellite and body area network applications / Étude et réalisation de antennes diélectriques pour les applications satellitaires et corps (BAN)Alam, Muhammad Faiz 02 July 2012 (has links)
Dans cette thèse, on vise deux types d'applications de l’antenne à résonateur diélectrique (DRA): 1) La réalisation d’un élément rayonnant pour un réseau phasé embarqué sur un véhicule terrestre ou un avion. Cet élément de base requiert une couverture en élévation supérieure à celle des éléments imprimés pour permettre une poursuite typique comprise entre ±70°. La couverture dans un cône large est assurée avec une bonne pureté de polarisation circulaire en alimentant l’antenne à travers deux ouvertures à fente en H orthogonales parfaitement découplées en bande X. 2) La deuxième structure est destinée à la diversité d’antennes dans le contexte des réseaux corporels embarqués ou Body Area Network (BAN). L’antenne à diversité combine une antenne fente en boucle avec un DRA ce qui permet dans un espace compact de réaliser des diagrammes de type “broadside” et “endfire” respectivement. Les alimentations considérées sont de 2 types; Soit purement planaire (microruban et coplanaire) soit mixte en combinant une alimentation coaxiale et une alimentation coplanaire. Caractéristiques principales des antennes à résonateur diélectrique (DRA): Pour répondre aux attentes des utilisateurs en termes de débit, les systèmes de communication sans fils se tournent vers des fréquences de plus en plus élevées. La conséquence de cette montée en fréquence est notamment l’augmentation des pertes au niveau des éléments conducteurs et donc une diminution de l’efficacité globale des systèmes de communication. Dans ces circonstances, les DRA offre de meilleurs résultats par rapport à d'autres familles d'antennes à base d’éléments métalliques. De plus, les DRA offrent des pertes diélectriques négligeables, elles sont peu sensibles aux variations de température et s’intègrent facilement sur des technologies de fabrication planaires / Technologies such as direct broad cast satellite system (DBSS), Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite communications , global positioning system (GPS), high accuracy airborne navigation system and a large variety of radar systems demand for high level of antenna performance. Similar is the requirement for upcoming land based wireless systems such as cellular and indoor communication systems that is needed some more specific and additional features added to the antenna to compensate for the deficiencies encountered in system's performance. Though metallic antennas are capable enough to fulfil all the operational requirements, however at very high frequencies and under hostile temperature conditions they are constrained to face certain limitations. To avoid these constraints the performance of Dielectric Resonator Antennas (DRAs) is evaluated and their new applications are proposed. In the thesis, two types of antenna applications are sought :-First is for tracking and satellite applications that needs a larger aperture coverage in elevation plane. This coverage is realized with a good CP purity by proposing two ports dual linearly polarized DRA working at X-band. The DRA is excited by two orthogonal H-shaped aperture slots yielding two orthogonal polarizations in the broadside direction. A common impedance bandwidth of 5.9% and input port isolation of -35 dB are obtained. The broadside radiation patterns are found to be highly symmetric and stable with cross polarization levels -15dB or better over the entire matching frequency band. The maximum measured gain is found to be 2.5dBi at 8.4 GHz.- The 2nd type of antenna is a dual pattern diversity antenna to be used in the Body Area Network (BAN) context. This antenna combines a slot loop and DRA yielding broadside and end-fire radiation patterns respectively. Based upon the feeding techniques, the DG antenna is further divided into two categories one with planar feeds and the other with non-planar feeds (slot loop excited by planar CPW but DRA excited by vertical monopole) .Both types are successfully designed and measured upon body when configured into different propagation scenarios. The non-planar feeds antenna allows wider common impedance bandwidths than the planar feeds (4.95% vs 1.5%).In both cases, a maximum value of DG=9.5dB was achieved when diversity performance tests were carried out in rich fading environments. This value is close to the one (10 dB) theoretically reached in a pure Rayleigh environment and was obtained with efficiencies of 70% and 85% for the slot loop and the DRA respectively. Therefore, we conclude that these antennas could be used on the shoulders or the chest of professional clothes (firemen, policemen, soldier) where full planar integration is not a key issue but where the communication must be efficient in harsh environments and for various gestures, positions and scenarios
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