Yes / A printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering is presented. A coplanar waveguide to coplanar strip transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before the dipole, was proposed. Simulated and measured data for the CWP-to-CPS balun as well as the measured performance of the RF switch are shown. It has demonstrated the switch capability to control the beam in the design of beam steering antenna array for mobile base station applications.

The objectives of this work were to investigate, design and implement beam steering antenna arrays for mobile and wireless applications using the genetic algorithm (GA) and particle swarm optimisation (PSO) techniques as optimisation design tools. Several antenna designs were implemented and tested: initially, a printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering was investigated. A coplanar waveguide (CPW) to coplanar strip (CPS) transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before it, was proposed. The measured performance of the RF switch was tested and the results confirmed its viability. Then two hybrid coupled PIN diode phase shifters, using Branchline and Rat-Race ring coupler structures, were designed and tested. The generation of four distinct phase shifts was implemented and studied. The variations of the scattering parameters were found to be realistic, with an acceptable ±2 phase shift tolerance. Next, antenna beam steering was achieved by implementing RF switches with ON or OFF mode functions to excite the radiating elements of the antenna array. The switching control process was implemented using a genetic algorithm (GA) method, subject to scalar and binary genes. Anti-phase feeding of radiating elements was also investigated. A ring antenna array with reflectors was modelled and analysed. An antenna of this type for mobile base stations was designed and simulation results are presented. Following this, a novel concept for simple beam steering using a uniform antenna array operated at 2.4 GHz was designed using GA. The antenna is fed by a single RF input source and the steering elements are reactively tuned by varactor diodes in series with small inductors. The beam-control procedure was derived through the use of a genetic algorithm based on adjusting the required reactance values to obtain the optimum solution as indicated by the cost function. The GA was also initially used as an optimisation tool to derive the antenna design from its specification. Finally, reactive loading and time modulated switching techniques are applied to steer the beam of a circular uniformly spaced antenna array having a source element at its centre. Genetic algorithm (GA) and particle swarm optimisation (PSO) processes calculate the optimal values of reactances loading the parasitic elements, for which the gain can be optimised in a desired direction. For time modulated switching, GA and PSO also determine the optimal on and off times of the parasitic elements for which the difference in currents induced optimises the gain and steering of the beam in a desired direction. These methods were demonstrated by investigating a vertically polarised antenna configuration. A prototype antenna was constructed and experimental results compared with the simulations. Results showed that near optimal solutions for gain optimisation, sidelobe level reduction and beam steering are achievable by utilising these methods. In addition, a simple switching process is employed to steer the beam of a horizontally polarised circular antenna array. A time modulated switching process is applied through Genetic Algorithm optimisation. Several model examples illustrate the radiation beams and the switching time process of each element in the array.

De nos jours, les antennes à réseaux transmetteurs attirent un grand intérêt pour de nombreuses applications civiles et militaires aux bandes de fréquence comprises entre 10 et 110 GHz (réseaux de communication 5G, liens point à point, radars, etc.).Le travail de thèse vise à faire des innovations dans la modélisation et la conception d'antennes à réseaux transmetteurs pour des applications en bande Ka (28-40 GHz). Il porte plus précisément sur le développement d'outils numériques pour l’analyse théorique des réseaux transmetteurs, la conception et la démonstration de plusieurs prototypes avec des fonctionnalités avancées, telles que des réseaux transmetteurs passifs (larges bandes ou à multifaisceaux) et actifs (à reconfiguration électronique).La première partie des travaux consiste en une analyse théorique des réseaux transmetteurs. Dans un premier temps, l’impact de la méthode de compensation de phase sur les performances des réseaux transmetteurs est étudié. La loi de compensation de phase de l’onde quasi-sphérique incidente sur l’ouverture du réseau transmetteur est calculée en utilisant deux méthodes nommées compensation à phase constante et compensation par ligne à retard, et nous montrons que cette dernière permet d’augmenter la bande passante du réseau transmetteur et de corriger les erreurs de dépointage du faisceau. Dans un second temps, le principe de fonctionnement des réseaux transmetteurs facettés est décrit en détail. La simulation numérique du réseau transmetteur à trois facettes est validée au travers de simulations électromagnétiques 3-D. Pour un certain angle d’inclinaison, nous montrons que la bande passante et la capacité de dépointage du réseau transmetteur sont améliorées au détriment du gain.La suite des travaux porte sur la conception et le prototypage de deux réseaux transmetteurs passifs, dont l’un à faisceau collimaté et très large bande et l’autre à quatre faisceaux fixes. Les deux réseaux transmetteurs sont basés sur une cellule élémentaire à 3bits qui assure une double fonction à savoir la compensation de phase et la conversion de la polarisation linéaire en circulaire. Le réseau passif à faisceau collimaté présente un gain mesuré de 33,8 dBi (correspondant à une efficacité d'ouverture de 51,2%) et une bande passante à -3 dB supérieure à 15,9%. La distribution de phase du réseau transmetteur à quatre faisceaux a été optimisée par un algorithme génétique afin d’avoir des faisceaux dépointés à ± 25° dans le plan horizontal et le plan vertical à la fréquence d’optimisation.La dernière partie des travaux vise la conception d’un réseau transmetteur reconfigurable à 27-31 GHz. Dans un premier temps, une cellule élémentaire active à quatre états de phase (2 bits) en polarisation linéaire a été conçue et validée expérimentalement. Elle est composée de six couches métalliques imprimées sur trois substrats. Les éléments rayonnants sont des antennes patch rectangulaires comprenant chacun deux diodes PIN pour contrôler la phase de transmission. Le principe de fonctionnement de la cellule élémentaire a été validé expérimentalement avec des pertes d’insertion minimales de 1.6-2,1 dB et une bande passante en transmission (à 3 dB) de 10-12,1% pour les quatre états de phase 0 °, 90°, 180° et 270°. Cette cellule a ensuite été utilisée pour la conception d’un réseau transmetteur reconfigurable comprenant 14 × 14 cellules unitaires et 784 diodes PIN. Un prototype a été réalisé et caractérisé, il présente un gain maximum mesuré de 19,8 dBi, correspondant à une efficacité d'ouverture de 23,5%, et une bande passante à 3 dB de 4,7 GHz (26,2-30,9 GHz). Malgré quelques éléments défaillants, ce prototype valide le principe de fonctionnement et la faisabilité de réseaux transmetteurs en bande Ka avec une quantification de phase de 2 bits et constitue une des premières réalisations de ce type dans l’état de l’art actuel. / Nowadays, transmitarray antennas are of great interest for many civil and military applications in frequency bands between 10 and 110 GHz (5G mobile networks, point-to-point communication systems, radars, etc.).This thesis aims to make major innovations in modeling and design of transmitarray antennas for Ka-band applications (28-40 GHz). It focuses on the development of numerical tools, and the design and demonstration of several prototypes with advanced functionalities, such as passive (broadband or multibeam) and active (at electronic reconfiguration) transmitarrays.The first part of the work consists of a theoretical analysis of the transmitarray antenna. In a first step, the impact of the phase compensation method on the performance of the transmitarray is studied. The phase compensation law of the quasi-spherical wave incident on the array aperture is calculated using two methods called constant phase compensation and true-time delay (TTD) compensation. The numerical results show that TTD compensation allows an increase of the transmitarrays bandwidth and a reduction of the beam squint as compared to constant phase-shift compensation. In a second step, the operating principle of facetted transmitarrays is described in detail. The numerical simulation of a 3-facet transmitarray is validated through 3-D electromagnetic simulations. For a certain facet angle, the bandwidth and the beam scanning capability of the TA are improved at the expense of the gain.The next step of the work concerns the design and prototyping of two passive transmitarray antennas, one with a collimated and a large bandwidth, and the other with four fixed beams. The two transmitarrays are based on a 3-bit unit-cell providing two functions, namely the phase compensation and the polarization conversion from linear to circular. The passive beam-collimated transmitarray exhibits a measured gain of 33.8 dBi (corresponding to an aperture efficiency of 51.2%) and a 3-dB gain-bandwidth larger than 15.9%. The quad-beam transmitarray phase distribution has been optimized by a genetic algorithm code coupled with an analytical tool. The array is designed to radiate four beams at ±25° in the horizontal and vertical planes at the optimization frequency.The last part of the work aims to the design of a 27-31 GHz reconfigurable transmitarray antenna. Initially, an active unit-cell with four phase states (2 bits) in linear polarization was designed and validated experimentally. It consists of six metal layers printed on three substrates. The radiating elements are rectangular patch antennas, each of them including two PIN diodes to control the transmission phase. The operating principle of the unit-cell has been experimentally validated with a minimum insertion loss of 1.6-2.1 dB and a 3-dB transmission bandwidth of 10-12.1% for the four phase states. 0°, 90°, 180° and 270°.Then, this unit-cell was used for the design of a reconfigurable transmitarray antenna comprising 14 × 14 unit cells and 784 PIN diodes. A prototype was realized and characterized, it presents a measured maximum gain of 19.8 dBi, corresponding to an aperture efficiency of 23.5%, and a 3-dB bandwidth of 4.7 GHz (26.2% at 30.9 GHz). Despite some faulty elements, this prototype validates the operating principle and the feasibility of Ka-band transmitarray antennas with a 2-bit phase quantization. It is one of the first demonstration of such an antenna in the current state of the art.

The objectives of this work were to investigate, design and implement beam steering antenna arrays for mobile and wireless applications using the genetic algorithm (GA) and particle swarm optimisation (PSO) techniques as optimisation design tools. Several antenna designs were implemented and tested: initially, a printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering was investigated. A coplanar waveguide (CPW) to coplanar strip (CPS) transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before it, was proposed. The measured performance of the RF switch was tested and the results confirmed its viability. Then two hybrid coupled PIN diode phase shifters, using Branchline and Rat-Race ring coupler structures, were designed and tested. The generation of four distinct phase shifts was implemented and studied. The variations of the scattering parameters were found to be realistic, with an acceptable ±2 phase shift tolerance. Next, antenna beam steering was achieved by implementing RF switches with ON or OFF mode functions to excite the radiating elements of the antenna array. The switching control process was implemented using a genetic algorithm (GA) method, subject to scalar and binary genes. Anti-phase feeding of radiating elements was also investigated. A ring antenna array with reflectors was modelled and analysed. An antenna of this type for mobile base stations was designed and simulation results are presented. Following this, a novel concept for simple beam steering using a uniform antenna array operated at 2.4 GHz was designed using GA. The antenna is fed by a single RF input source and the steering elements are reactively tuned by varactor diodes in series with small inductors. The beam-control procedure was derived through the use of a genetic algorithm based on adjusting the required reactance values to obtain the optimum solution as indicated by the cost function. The GA was also initially used as an optimisation tool to derive the antenna design from its specification. Finally, reactive loading and time modulated switching techniques are applied to steer the beam of a circular uniformly spaced antenna array having a source element at its centre. Genetic algorithm (GA) and particle swarm optimisation (PSO) processes calculate the optimal values of reactances loading the parasitic elements, for which the gain can be optimised in a desired direction. For time modulated switching, GA and PSO also determine the optimal on and off times of the parasitic elements for which the difference in currents induced optimises the gain and steering of the beam in a desired direction. These methods were demonstrated by investigating a vertically polarised antenna configuration. A prototype antenna was constructed and experimental results compared with the simulations. Results showed that near optimal solutions for gain optimisation, sidelobe level reduction and beam steering are achievable by utilising these methods. In addition, a simple switching process is employed to steer the beam of a horizontally polarised circular antenna array. A time modulated switching process is applied through Genetic Algorithm optimisation. Several model examples illustrate the radiation beams and the switching time process of each element in the array.