This research focuses on radio wave propagation at millimeter-wave frequencies. A measurement based channel characterization approach is taken in the investigation. First, measurement techniques are analyzed. Three types of measurement systems are designed, and implemented in measurement campaigns: a narrowband measurement system, a wideband measurement system based on Vector Network Analyzer, and sliding correlator systems at 5.8+AH4AXA-mbox{GHz}, 38+AH4AXA-mbox{GHz} and 60+AH4AXA-mbox{GHz}. The performances of these measurement systems are carefully compared both analytically and experimentally. Next, radio wave propagation research is performed at 38+AH4AXA-mbox{GHz} for Local Multipoint Distribution Services (LMDS). Wideband measurements are taken on three cross-campus links at Virginia Tech. The goal is to determine weather effects on the wideband channel properties. The measurement results include multipath dispersion, short-term variation and signal attenuation under different weather conditions. A design technique is developed to estimate multipath characteristics based on antenna patterns and site-specific information. Finally, indoor propagation channels at 60+AH4AXA-mbox{GHz} are studied for Next Generation Internet (NGI) applications. The research mainly focuses on the characterization of space-time channel structure. Multipath components are resolved both in time of arrival (TOA) and angle of arrival (AOA). Results show an excellent correlation between the propagation environments and the channel multipath structure. The measurement results and models provide not only guidelines for wireless system design and installation, but also great insights in millimeter-wave propagation. / Ph. D.

L'objectif de cette thèse est de réaliser un système radio-sur-fibre bidirectionnel fonctionnant dans la bande des fréquences millimétriques autour de 60 GHz. La solution proposée est basée sur l'utilisation d'une photodiode PIN en tant que mélangeur optoélectronique. Une étude théorique associée à une caractérisation non-linéaire et large bande de la photodiode a permis de modéliser le comportement mélangeur de la photodiode. Le modèle de photodiode obtenu a ensuite été utilisé pour optimiser les performances du mélangeur optoélectronique puis du système radio-sur-fibre complet. Des mesures expérimentales ont permis de vérifier la compatibilité du système proposé avec les spécifications du standard ECMA 387 proposé pour régir la création de réseaux locaux aux fréquences de 60 GHz, pour au moins les deux premiers débits proposés (394 Mb/s et 794 Mb/s).

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

This dissertation presents the design and implementation of circuits and transceivers in CMOS technology to enable many new millimeter-wave applications. A simple approach is presented for accurately modeling the millimeter-wave characteristics of transistors that are not fully captured by contemporary parasitic extraction techniques. Next, the integration of a low-power 60-GHz CMOS on-off keying (OOK) receiver in 90-nm CMOS for use in multi-gigabit per second wireless communications is demonstrated. The use of non-coherent OOK demodulation by a novel demodulator enabled a data throughput of 3.5 Gbps and resulted in the lowest power budget (31pJ/bit) for integrated 60-GHz CMOS OOK receivers at the time of publication. Also presented is the design of a high-power, high-efficiency 45-GHz VCO in 45-nm SOI CMOS. The design is a class-E power amplifier placed in a positive feedback configuration. This circuit achieves the highest reported output power (8.2 dBm) and efficiency (15.64%) to date for monolithic silicon-based millimeter-wave VCOs. Results are provided for the standalone VCO as well as after packaging in a liquid crystal polymer (LCP) substrate. In addition, a high-power high-efficiency (5.2 dBm/6.1%) injection locked oscillator is presented. Finally, the design of a 2-channel 45-GHz vector modulator in 45-nm SOI CMOS for LINC transmitters is presented. A zero-power passive IQ generation network and a low-power Gilbert cell modulator are used to enable continuous 360° vector generation. The IC is packaged with a Wilkinson power combiner on LCP and driven by external DACs to demonstrate the first ever 16-QAM generated by outphasing modulation in CMOS in the Q-band.

This dissertation presents a novel large signal modeling approach which can be used to accurately model CMOS transistors used in millimeter-wave CMOS power amplifiers. The large signal model presented in this work is classified as an empirical compact device model which incorporates temperature-dependency and device periphery scaling. These added features allow for efficient design of multi-stage CMOS power amplifiers by virtue of the process-scalability. Prior to the presentation of the details of the model development, background is given regarding the 90nm CMOS process, device test structures, de-embedding methods and device measurements, all of which are necessary preliminary steps for any device modeling methodology. Following discussion of model development, the design of multi-stage 60GHz Class AB CMOS power amplifiers using the developed model is shown, providing further model validation. The body of research concludes with an investigation into designing a CMOS power amplifier operating at frequencies close to the millimeter-wave range with a potentially higher-efficiency class of power amplifier operation. Specifically, a 24GHz 130nm CMOS Inverse Class F power amplifier is simulated using a modified version of the device model, fabricated and compared with simulations. This further demonstrates the robustness of this device modeling method.

Driven by the ever growing consumer wireless electronics market and the need for higher speed communications, the 60-GHz technology gifted with an unlicensed 9 GHz frequency band in the millimeter-wave spectrum has emerged as the next-generation Wi-Fi for short-range wireless communications. High-performance, cost-effective, and small form-factor 60-GHz antenna systems for portable devices are key enablers of this technology. This work presents various antenna architectures built on low-cost organic packages. Planar end-fire switched beam antenna modules that can easily conform to various surfaces inside a wireless device platform are developed. The planar antenna package is realized on thin flexible LCP dielectrics. One design is based on a planar Yagi-Uda antenna element and the second on a tapered slot antenna element. A low-loss microstrip-to-slot via transition is designed to provide wide impedance matching for end-fire antenna paradigms. The novel transition utilizes the slow-wave concept to provide unbalanced to balanced mode conversion as well as impedance matching. It is demonstrated that the planar antenna packages may be even integrated with active circuits that are cavity recessed inside the thin dielectric. A compact switched-beam antenna module is demonstrated. The first-ever integrated mm-wave active antenna module on organic package capable of generating both broadside and end-fire radiation is also developed in this work. Both broadside and end-fire radiators are co-designed and integrated into a single multilayer package to achieve optimal directivity, efficiency and frequency bandwidth and yet maintain excellent isolation between the two radiators. Post-wall cavities, image theory and dielectric slab modes concepts are invoked to optimize these functions. Active circuitry are integrated into the same package to add control functions such as beam switching, and also amplify the packaged-antenna gain when operated either as a transmitter or a receiver. A significant challenge in the design of antenna systems for wireless platforms is the assessment of embedded antenna performance, that is, the proximity effects of the platform chassis on the embedded antenna. Various antennas are mounted at different locations inside a laptop computer chassis: modeling and experimental studies are carried out to characterize this problem that is apparent to an antenna behind a radome. Air traffic control radars usually require cavity filters that can handle high power and low in-band insertion loss while providing enough out-band rejection to prevent interference with neighboring channels. Such radars that operate in the S-band consist of filter banks frequency micro electromechanical systems (RF-MEMS) switches. Evanescent-mode mode cavity resonators are loaded with RF-MEMS tuning capacitance networks to control the resonant frequency of a second-order bandpass filter. The second part is the design of a novel cavity filter architecture for enhanced selectivity near the passband. It is a second-order folded cavity resonator bandpass filter with magnetic source-load cross coupling. This filter can have at least two finite transmission zeros near the passband.

With rapid advances in semiconductor technologies and packaging schemes, wireless products have become more versatile, portable, inexpensive, and user friendly over last few decades. However, the ever-growing demand of consumers to share information efficiently at higher speeds requires higher data rates, increased functionality, lower cost, and more reliability. The 60-GHz-frequency band, with 7 GHz license-free bandwidth addresses, such demands, and promises a low-cost multi-Gbps wireless transmission with a power budget in the order of 100 mW. This dissertation presents the systematic development of key building blocks and integrated 60-GHz-receiver solutions. Two different approaches are investigated and implemented in this dissertation: (1) low-cost SiGe-based direct-conversion low-power receiver front-end utilizing gain-boosting techniques in the front-end low-noise amplifier, and (2) CMOS-based heterodyne receiver front-end suitable for high-performance single-chip 60 GHz transceiver solution. The ASK receiver chip, implemented using 0.18 ?m SiGe, presents a complete antenna-to-baseband multi-gigabit 60 GHz solution with the lowest reported power budget (25 pJ/bit) to date. The subharmonic direct conversion front-end, implemented using 0.18 ?m SiGe, presents excellent conversion properties with a 4 GHz DSB RF bandwidth. On the other hand, the CMOS heterodyne implementation of the 60 GHz front-end receiver, targeted towards a robust, single-chip, high-performance, low-power, and integrated 60 GHz transceiver solution, presents the most wideband receiver front-end reported to date. Finally, different multi-band and tunable millimeter-wave circuits are presented towards the future implementation of cognitive and multi-band millimeter-wave radio.

The purpose of this thesis was to investigate the feasibility of a wireless architectural approach for intra-vehicle communications. The current wired architecture was compared to a wireless approach based on three prominent wireless protocols, namely Bluetooth Low-Energy, Ultra Wide-Band, and 60 GHz Millimeter wave technology. The evaluation was focused on their potential use within the intra-vehicle domain, and judged by characterizing properties such as frequency, bandwidth utilization, and power efficiency. A theoretical study targeting the propagating behavior of electromagnetic waves was also involved. In particular, wireless behavior has been investigated both in general aspects as well as specifically aimed towards the intra-vehicle application. The theoretical study was then concluded and presented with a course of action regarding wireless connectivity. Beneficial design considerations, potentials and challenges were highlighted together with a discussion on the feasibility of a wireless architectural approach. Suggestions for future work and research have been given, which include further expansion of targeted protocols, alleviating the restricted security aspects, and extend the physical aspects onto more software based approaches.

Récemment la bande 60 GHz a été mise en avant pour le développement des réseaux de communication sans fil centrés sur le corps humain. Cet intérêt de la bande 60 GHz pour les applications BAN (Body Area Network) s'explique par les avantages clefs qu'elle procure par rapport aux bandes de fréquence plus basses (possibilité de débits de données supérieurs à 7 Gbit/s, réduction des interférences avec les réseaux voisin, compacité des dispositifs, etc). Le nombre d'application de communication BAN est amené à croître dans les années à venir avec le déploiement de la 5ème génération de réseaux de télécommunications mobiles. Afin de protéger efficacement les utilisateurs des expositions générées par ces applications BAN à 60 GHz, il est nécessaire de se pencher sur les problématiques de réduction du couplage corps/antennes, mais également sur l'évaluation et la quantification du niveau d'exposition du corps à 60 GHz. Pour cela, les travaux de thèse ont été organisés suivant trois axes de recherche : le premier consiste à mettre en évidence et à quantifier l'impact de certains choix de conception en matière d'antennes sur le couplage avec le corps humain ; le second porte sur les outils et les méthodes utilisés pour estimer l'impact thermique d'une exposition électromagnétique 60 GHz sur le fantôme équivalent de la peau ; et le troisième propose une nouvelle approche à la fois dosimétrique et thermique pour évaluer et analyser le couplage corps/antennes en bande millimétrique. / The 60-GHz frequency band has been identified recently as attractive for body centric wireless communication development. Indeed, this band has several key advantages compared to lower frequency bands as high data rates above 7 Gbit/s, low risks of interference with neighboring wireless networks and compact devices. With the development of the future 5th generation of mobile networks in the millimeter-wave band, the number of BAN applications at 60 GHz should increase. To avoid health effects and protect user against an electromagnetic exposure of BAN devices at 60 GHz, the reduction of the coupling between human body and antennas, as well as the evaluation and quantification of exposure are main research aspect of the thesis. The main thesis contributions are divided in three parts: a quantification of antenna design effects on the interactions between human body and antennas; a study of tools and methods used to assess thermal effects due to 60 GHz exposure on a skin-equivalent phantom; and a new dosimetric and thermal approach to evaluate interaction between human body and BAN antennas at 60 GHz.

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.