This dissertation explores the role of polarization, combining, and equalization operating over frequency-selective channels to improve the reliability of wireless communications systems in terms of BER for two applications: 5G mobile networks (operating in the mmWave band and NR FR1), and aeronautical mobile telemetry systems (operating in L band). The equivalent discrete-time models for a variety of spatial combining techniques at 5G mmWave bands were derived to investigate the performance of co-located cross-polarized antenna elements when polarization diversity is used and also when a combination of spatial and cross-polarized antennas is exploited. In both cases, ML combining has the lowest BER and EPC produced the worst results. The use of co-located cross-polarized antenna elements also is examined in 5G FR1 assuming post-FFT processing of the two antenna element outputs in a mobile-to-mobile setting. The optimum strategy, in the ML sense, for incorporating the two antenna outputs is developed. The optimum combining strategy together with a FDE is compared to the traditional combining techniques: MRC, EGC, and SC, where the last two also require a FDE. Computer simulations performed over a stochastic channel model with polarization state information show that the difference between ML detection and MRC (the best performing methods) and SC with FDE (the worst performing method) is 2 dB. The similar results were observed with pilot based channel estimators, however the difference in this case was the presence of a BER floor at low values of $N_0$ and caused by channel estimation errors. In aeronautical mobile telemetry applications, the ML combiner is derived and shown to be equivalent to the summing the outputs of two filters matched to the channels in the horizontal and vertical polarization states. For historical reasons, current systems combine right-hand and left-hand circularly polarized antenna feed outputs using a MRC. To compare the two combining approaches, the aeronautical telemetry multipath channel was extended to include polarization state information. The simulation results for SOQPSK-TG with a CMA equalizer show that the post-equalizer BER for the two approaches is the same.

L’objectif de ce travail est de concevoir et de caractériser un front-end millimétriqueutilisant des lignes de propagation à ondes lentes S-CPW optimisées en technologies CMOS avancées.Ces lignes présentant des facteurs de qualité 2 à 3 fois supérieurs à ceux des lignes classiques de typemicroruban ou CPW.Dans le premier chapitre, l’impact de l’évolution des noeuds technologiques CMOS sur lesperformances des transistors MOS aux fréquences millimétriques et sur les lignes de propagation ainsiqu’un état de l’art concernant les performances des front-end sont présentés. Le deuxième chapitreconcerne la réalisation des lignes S-CPW dans différentes technologies CMOS et la validation d’unmodèle phénoménologique électrique équivalent. Le troisième chapitre est dédié à la conceptiond’amplificateurs de puissance à 60 GHz utilisant ces lignes S-CPW en technologies CMOS 45 et65 nm. Cette étude a permis de mettre en évidence l’apport des lignes à ondes lentes aux performancesdes amplificateurs de puissance fonctionnant dans la gamme des fréquences millimétriques. Uneméthode de conception basée sur les règles d’électro-migration et permettant une optimisation desperformances a été développée. Finalement, un amplificateur faible bruit et un commutateur d’antennetravaillant à 60 GHz et à base de lignes S-CPW ont été conçus en technologie CMOS 65 nm afin degénéraliser l’impact de ce type de lignes sur les performances des front-end millimétriques. / The objective of this work is to design and characterize a millimeter-wave front-end usingthe optimized slow-wave transmission lines S-CPW in advanced CMOS technologies. The qualityfactor of these transmission lines is twice to three times higher than that of the conventionaltransmission lines such as microstrip lines and coplanar waveguides.In the first chapter, the influence of CMOS scaling-down on the performance of transistors atmillimeter-wave frequencies and on the transmission lines was studied. In addition, a state of the artwith regard to the performance of the front-end was presented. The second chapter concerns about therealization of the S-CPW lines in different CMOS technologies and the validation of an electricalequivalent model. The third chapter is dedicated to the design of 60-GHz power amplifiers using theseS-CPW lines in CMOS 45 and 65 nm technologies. This study highlighted the performanceenhancement of power amplifiers operating at millimeter-wave frequencies by using the slow-wavetransmission lines. A design method based on the electro-migration rules was also developed. Finally,a low noise amplifier and an antenna switch operating at 60 GHz were designed in CMOS 65 nm inorder to generalize the impact of such transmission lines on the performance of the millimeter-wavefront-end.

Yes / A feasibility study of a novel configuration for a super-wide impedance planar antenna is presented based on a 2 × 2 microstrip patch antenna (MPA) using CST Microwave Studio. The antenna comprises a symmetrical arrangement of four-square patches that are interconnected to each other with cross-shaped high impedance microstrip lines. The antenna array is excited through a single feedline connected to one of the patches. The proposed antenna array configuration overcomes the main drawback of conventional MPA with a narrow bandwidth that is typically <5%. The antenna exhibits a super-wide frequency bandwidth from 20 GHz to 120 GHz for S11 < −15 dB, which corresponds to a fractional bandwidth of 142.85%. The antenna’s performance of bandwidth, impedance match, and radiation gain were enhanced by etching slots on the patches. With the inclusion of the slot, the maximum radiation gain and efficiency of the MPA increased to 15.11 dBi and 85.79% at 80 GHz, which showed an improvement of 2.58 dBi and 12.54%, respectively. The dimension of each patch antenna was 4.3 × 5.3 mm2 . The results showed that the proposed MPA is useful for various existing and emerging communication systems such as ultra-wideband (UWB) communications, RFID systems, massive multiple-output multiple-input (MIMO) for 5G, and radar systems. / This work was partially supported by the Innovation Program under grant agreement H2020-MSCA-ITN-2016 SECRET-722424 and financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E022936/1.

Avec l'ouverture de la bande 57-66 GHz en Europe, de nouvelles technologies de communication sans fil à haut débit sont en cours de développement. De nombreux avantages liés à cette bande de fréquence ont notamment conduit à envisager la transposition du principe de l'identification par radiofréquence (RFID) en bande millimétrique : la MMID. Les réglementations internationales font notamment apparaître une bande passante commune de 5 GHz qui permettrait la mise en place de solutions universelles. De plus la sécurisation des communications point-à-point et la directivité des réseaux d'antennes offrent des perspectives intéressantes.Les travaux présentés dans cette thèse visent à contribuer au développement de la MMID. Ils soulignent les principaux verrous de cette technologie et présentent les différentes solutions proposées qui couvrent de multiples aspects : conception d'antennes et de réseaux d'antennes, conception de prototypes de tags MMID passifs, caractérisation et méthodologie de mesure dont la conception intégrale d'un banc de mesure en bande V, amélioration des performances des tags, et étude de fonctionnalités de capteur intégrées aux tags. Les différents prototypes de tags MMID fabriqués ont permis de réaliser des communications passives de type rétro-modulation jusqu'à 20 cm. De plus, des fonctions de capteur d'humidité et capteur de pression intégrées aux tags MMID ont été montrées expérimentalement. L'ensemble de ces résultats ouvre la voie à de nouvelles perspectives pour les domaines des télécommunications et des réseaux de capteurs en bande millimétrique. / With the opening of the 57-66 GHz band in Europe, new high data-rate wireless communication technologies are currently under development. Numerous advantages linked to the frequency band conducted to consider the transposition of the radiofrequency identificaion (RFID) principle to the millimeter frequency band: the MMID. The international regulations provide a common bandwidth of 5 GHz allowing universal solutions. Moreover, the communication security of point-to-point networks and the directivities of the antennas present interesting perspectives.The presented work in this thesis looks for contributing to the development of MMID. The work underlines the principal locks of this technology and it presents the different proposed solutions covering multiple aspects: conception of antennas and antennas arrays, conception of MMID tags prototypes, characterization and measurement methodology including the complete conception of a measurement bench in V-band, improvement of the tags performances and study of sensing functionalities integrated in the tags. Different prototypes of MMID tags are fabricated and passive communications based on the backscattering of the tags were demonstrated up to 20 cm. In addition, humidity and pressure sensing functionalities were proved by experimentations. The overall of these results pave the way for new perspectives for the wireless communication domain and sensors networks in the millimeter-wave band.