Dans le cadre des communications numériques sans fil, la vitesse d’échange de données est plus que jamais une caractéristique critique du système. Une augmentation du débit est donc nécessaire pour le développement de nouvelles applications, comme le «Wireless HD» qui doit rendre possible la transmission sans fil de gros volumes de données, telles que de la vidéo «non-compressée» à haute définition, à très haut débit (1-2 Gbps). La bande de fréquence centrée à 60 GHz semble être une solution préférentielle pour répondre à un tel besoin de par sa bande de fréquence disponible (9 GHz). Pour cela, il est nécessaire de disposer de technologies performantes pour l’intégration de systèmes d’émission réception (front-ends) millimétriques pour ces communications à très haut débit. L’objectif de cette thèse est de participer à la réalisation d’un système antennaire très directif à 60 GHz par la conception combinée d’une antenne et d’un filtre, et l’intégration de cette fonction grâce à un même procédé technologique. La conception et l’intégration combinées de l’antenne et du filtre participeront à améliorer le rendement global du sous-système destiné à des applications très haut débit à 60 GHz. Cette thèse, intitulée «Conception de fonctions combinées filtre-antenne pour les communications haut débit à 60 GHz», a été réalisée au sein du laboratoire XLIM, en collaboration avec le SPCTS pour les aspects technologiques, dans le cadre d’un projet régional. / The 60 GHz unlicensed spectrum between 57 and 66 GHz has received a lot of attention over the last years for enabling short-range and over 1-Gbps high-speed wireless communications. In addition to the high-data rates that can be accomplished in this spectrum, many other benefits such as high security communications are foreseen. In general, this frequency band is destined to low power and short range fixed or mobile applications. To benefit from high-speed within a compact device, it is required to realize a subsystem combining a directional antenna and a multiplexer with the same technological process. The 3D ceramic stereo lithography process has been selected to ensure the dimensional accuracy and limit the inevitable dispersions. This thesis contributes to achieve directional antennas at 60GHz by a combined antenna design and filter, and perform this function in the same technology the 3D ceramic stereo lithography process when connecting the filter with the antenna. Therefore, the first challenge is to design and to manufacture the primary feed of the directive antenna and the channel filters using the 3D ceramic process. The second challenge is to combine the primary feed and the 4 channel filters to form a single object. The filter-antenna subsystem allows to have a directivity of approximately 14 dBi. Therefore, the radiation of the horn antenna remains unchanged over the whole frequency band [57-66]GHz by associating the manifold multiplexer. The filter-antenna subsystem provides a return loss better than 10 dB at each port.

The aim of this thesis is the development of the workplace for the complex permittivity measurement by free space method. At the beginning of this thesis, the method is described. Further attention is focused on the discussions concerning electromagnetic properties of materials, comparison of the methods used for complex permittivity measurement, interactions of planar electromagnetic wave with planar infinite dielectric slab of general environment and description of radiation patterns of microwave antennas. In the rest of the thesis, the measuring workplace for the free space method is designed and fabricated. A pyramidal horn antenna is selected as a radiator. The antenna is designed with coax to waveguide transition in CST Microwave Studio, and than fabricated in two samples and measured. Finally, the fabricated measuring workplace is exploited for the complex permittivity measurement.

The purpose of the thesis is to design transmitting antenna based on septum polarizer solution for indoor measurement range. The antenna is considered for both senses of circular polarization. The design is divided into three main sections. First section is devoted to analysis and selection of a suitable waveguide. Ridge waveguide as a crucial part of a septum polarizer is mentioned in this section. Second part is the most critical; here the septum polarizer is analyzed and based on simple procedure also designed. Two suitable horn apertures are then developed as a part of the third section. Individual transmitting antenna parts are assembled together into one model and simulated with excellent results for axial ratio, cross-polarization discrimination, return loss and isolation between ports.

The presented master’s thesis deals with antennas transmitting energy along conductive materials. Surface waves are used for energy transmission. According to its properties, the horn antenna was chosen for the problem solution. This thesis includes the theoretical analysis of surface waves, waveguides and horn antennas. The concept of antennas includes the comparison of two different materials and two different frequencies. From the set of 8GHz antennas, the structure of two antennas where one wearing the other was chosen as the most suitable. The FoamClad material was also selected due to achievement of better parameters and properties then material CuClad. This structure was designed by two identical horn antennas where the energy between them is transmitted via slot. The suitable feeding and parallel plates were designed, and further the current structure was modified to SIW structure. The designed antenna was manufactured and its properties were measured for further comparison with simulation results. Furthermore, achieved differences between simulated and real antenna are discussed.

No description available.

The band around 60 GHz is interesting for BAN applications mainly for lowerinterference than at microwave frequencies, wide available band adapted to On-Off Keying(OOK) modulation for low energy consumption and low data rate communication (under10 Mbps), antenna miniaturization. Nevertheless, due to high attenuation at this frequency,the design of a reliable and energy-effective communications for BANs requires a detailedanalysis of the body channel. A planar and compact SIW horn antenna was designed and usedfor body channel measurements at 60 GHz. The main contribution in the antenna design is thebandwidth enhancement covering the whole available band around 60 GHz compared to thesame antenna type available at this frequency. The on-body measurements with this antennashow that short-distance and LOS (Line Of Sight) links are possible at 60 GHz. The bodydynamic is taken into account by statistical off-body channel measurements. For the firsttime, measurements are done for the same scenarios at 60 GHz and another frequency in theUltra WideBand suitable with OOK impulse radio modulation. By taking into accounttransmission power standards and low power consumption receivers sensitivity in theliterature, the potentiality of 60 GHz for BAN is shown with an outage probability lower than8 % whereas this parameter is lower than 15 % at 4 GHz. When characterizing antenna onbody, difficulties arise for antenna de-embedding due to the antenna-body coupling. In fact,the antenna gain depends on transmitter-receiver distance on body. For the first time, aformulation of the vertical dipole gain on body is given. Also a new theoretical approachbased on the complex images method is proposed to compare two types of canonical antennaradiating on body. A vertical dipole and different rectangular apertures are normalizedthrough their input impedance with the same accepted power. The aperture input impedanceformulation has been developed during this study. The aperture efficiencies are 10% higherwhen antennas are at a height lower than 3 mm above the body phantom. The received powerincreases with the antenna size only for phantom direct touch, the difference among antennasis lower than 4 dB for the considered antennas limited with a monomode configuration. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Ultra wideband (UWB) technology plays a significant role in wireless communication. The complex antenna transfer function (CATF) of an UWB antenna provides important information required for better channel designs and communication systems. In this dissertation the CATF of a Double ridge guide horn (DRGH) antenna is determined and used as a standard antenna for UWB measurements. Two methods were used: the two antenna method in an anechoic chamber and a modified gain-transfer method in a compact antenna test range (CATR). Measurements were performed with a vector network analyser (VNA) in the frequency domain, in the anechoic chamber and the CATR. The distance measurements required to calculate the CATF from the S-parameter measurements were performed in the time domain. The CATF of the standard antenna was determined using two identical antennas and then it was shown that a modified gain-transfer method can be used to determine the CATF of any unknown antenna in a CATR, using the standard antenna as a reference. Some of the challenges were to obtain the correct equations and measurement method to obtain the CATF in a CATR. The standard antenna was used to investigate uncertainty contributions for the measurements in the CATR. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Electrical, Electronic and Computer Engineering / unrestricted

This thesis deals with the design of lens antennas for automotive radar in 77 GHz bandwidth. The work explains methods of designing waveguides as well as horn antennas and dielectric lens. A simulation of three designed horn antennas is performed in CST Microwave Studio. Antennas with spherical and hyperbolical lens are simulated as well and subsequently optimized for maximal gain. The thesis also investigates effects of the lens permittivity on its properties. Furthermore, the work deals with a design of an antenna system with minimalized antenna coupling. Nylon, ABS and photopolymer lens are designed and compared afterwards. ABS and photopolymer lens were produced by 3D print

This master thesis deals with a study of directional antennas, followed by their design and optimalization of horn antenna based on SIW for Ka band (26,5- 40 GHz). The first part of the thesis contains the theoretical analysis of the different types of directional antennas, also the SIW technology is described here. It also describes the 3D printing technology by means of which the final antenna should be made. The next part of this work is about design of horn antenna based on SIW. Simulation and optimization of the antenna will be done using the CST Microwave Studio. The final part of the thesis deals with evaluation of achieved results.

This master thesis deals with a study of directional antennas, followed by their design and optimization of horn antenna based on SIW for Ka band (26,5- 40 GHz). The first part of the thesis contains the theoretical analysis of the different types of directional antennas, also the SIW technology is described here. It also describes the 3D printing technology by means of which the final antenna should be made. The next part of this work is about design of horn antenna based on SIW. Simulation and optimization of the antenna will be done using the CST Microwave Studio. The horn antenna was modeled with three different dielectric loads. The horn antenna with an experimental triangular dielectric load was chosen for fabrication. The fabricated antenna has reached almost the whole bandwidth to cover Ka. The antenna gain was 9,38 dBi for 33 GHz frequency.