This thesis presents the design of radio-frequency (RF) tunable active inductors (TAIs) with independent inductance (L) and quality factor (Q) tuning capability, and their application in the design of RF tunable phase shifters and directional couplers for wireless transceivers. The independent L and Q tuning is achieved using a modided gyrator-C architecture with an additional feedback element. A general framework is developed for this Q- enhancement technique making it applicable to any gyrator-C based TAI. The design of a 1.5V, grounded, 0.13um CMOS TAI is presented. The proposed circuit achieves a 0.8nH-11.7nH tuning range at 2GHz, with a peak-Q in excess of 100. Furthermore, printed and integrated versions of tunable positive/negative refractive index (PRI /NRI) phase shifters, are presented in this thesis. The printed phase shifters are comprised of a microstrip transmission-line (TL) loaded with varactors and TAIs, which, when tuned together, extends the phase tuning range and produces a low return loss. In contrast, the integrated phase shifters utilize lumped L-C sections in place of the TLs, which allows for a single MMIC implementation. Detailed experimental results are presented in the thesis. As an example, the printed design achieves a phase of -40 to +34 degrees at 2.5GHz. As another application for the TAI, a reconfigurable CMOS directional coupler is presented in this thesis. The proposed coupler allows electronic control over the coupling coefficient, and the operating frequency while insuring a low return loss and high isolation. Moreover, it allows switching between forward and backward operation. These features, combined together, would allow using the coupler as a duplexer to connect a transmitter and a receiver to a single antenna. Finally, a planar electronically steerable patch array is presented. The 4-element array uses the tunable PRI/NRI phase shifters to center its radiation about the broadside direction. This also minimizes the main beam squinting across the operating bandwidth. The feed network of the array uses impedance transformers, which allow identical interstage phase shifters. The proposed antenna array is capable of continuously steering its main beam from -27 to +22 degrees of the broadside direction with a gain of 8.4dBi at 2.4GHz.

This thesis presents the design of radio-frequency (RF) tunable active inductors (TAIs) with independent inductance (L) and quality factor (Q) tuning capability, and their application in the design of RF tunable phase shifters and directional couplers for wireless transceivers. The independent L and Q tuning is achieved using a modided gyrator-C architecture with an additional feedback element. A general framework is developed for this Q- enhancement technique making it applicable to any gyrator-C based TAI. The design of a 1.5V, grounded, 0.13um CMOS TAI is presented. The proposed circuit achieves a 0.8nH-11.7nH tuning range at 2GHz, with a peak-Q in excess of 100. Furthermore, printed and integrated versions of tunable positive/negative refractive index (PRI /NRI) phase shifters, are presented in this thesis. The printed phase shifters are comprised of a microstrip transmission-line (TL) loaded with varactors and TAIs, which, when tuned together, extends the phase tuning range and produces a low return loss. In contrast, the integrated phase shifters utilize lumped L-C sections in place of the TLs, which allows for a single MMIC implementation. Detailed experimental results are presented in the thesis. As an example, the printed design achieves a phase of -40 to +34 degrees at 2.5GHz. As another application for the TAI, a reconfigurable CMOS directional coupler is presented in this thesis. The proposed coupler allows electronic control over the coupling coefficient, and the operating frequency while insuring a low return loss and high isolation. Moreover, it allows switching between forward and backward operation. These features, combined together, would allow using the coupler as a duplexer to connect a transmitter and a receiver to a single antenna. Finally, a planar electronically steerable patch array is presented. The 4-element array uses the tunable PRI/NRI phase shifters to center its radiation about the broadside direction. This also minimizes the main beam squinting across the operating bandwidth. The feed network of the array uses impedance transformers, which allow identical interstage phase shifters. The proposed antenna array is capable of continuously steering its main beam from -27 to +22 degrees of the broadside direction with a gain of 8.4dBi at 2.4GHz.

Wireless communication is witnessing tremendous growth with the proliferation of various standards covering wide, local, and personal area networks, which operate at different frequency bands. Future wireless terminals will not only need to support multiple standards, but also need to be multi-functional to keep pace with the demands of the consumers. For such an implementation, the local oscillator (LO) turns out to be the bottleneck, which must exhibit frequency agility by generating a very wide range of carrier frequencies in order to access all the specified communication standards. This dissertation presents various design techniques to realize compact low-cost low-power and broadband oscillators in silicon-based technologies. The two most suitable techniques for broadband signal generation: (1) Use of widely tunable active inductor, and (2) Use of switched resonator have been thoroughly evaluated. A fully reconfigurable active inductor with a widely tunable feedback resistor has been proposed. Using the proposed tunable active inductor in a VCO generates frequency tuning ranges higher than 100%, and helps achieve the highest PFTN Figure-of-Merit among Si-based active inductor VCOs reported in literature till date. The large-signal non-linearity of the active inductor has been utilized to develop the first reported broadband harmonic active inductor-based VCO. The degradation of phase noise due to active inductors is partially solved by a noise optimization guideline for active inductors. Utilizing the low saturation voltage of HBT technologies and high-Q short line inductors seems to be very useful to reduce power consumption of cross-coupled VCOs while achieving low phase noise performance simultaneously.

Ce travail de thèse entre dans le cadre de projets nationaux et internationaux de radioastronomie d'une manière générale et en particulier dans celui de SKA (Square Kilometre Array). La conception de circuits intégrés d’applications spécifiques devient de plus en plus importante dans ce domaine. La première étape de ce travail consiste à une étude bibliographique sur les inductances actives intégrées et leurs principales applications dédiées à la radioastronomie. Cette étude a permis de faire un état de l'art. Cet état de l'art a fait ressortir que l'intégration de certaines fonctions s'avère particulièrement difficile voire impossible dès lors que l'utilisation d'une inductance est nécessaire. Ceci est essentiellement dû à la taille importante des inductances. Parmi ces fonctions, nous avons le filtrage, certains types de transceivers, le temps de retard, etc. Or ces fonctions sont très importantes dans une architecture de radiofréquence propre aux réseaux d'antennes phasées. Ce travail de thèse est donc consacré à l'étude et la conception de ces différentes fonctions à l'aide des inductances actives basées sur des topologies à gyrateurs en technologie SiGeC 0,25 μm afin de palier aux problèmes d'intégration. Une des finalités de cette thèse est aussi de montrer que la consommation de ce procédé d'intégration n’est pas si excessive pour ces applications, par rapport à l’utilisation d’inductances localisées intégrées occupant une surface importante sur le substrat. Ce dernier point sera un résultat très important pour les projets où la très haute intégration à bas coût est nécessaire, point clé de réussite des réseaux phasés denses du projet international SKA. / This thesis work is part of national and international projects of radio-astronomy in general and in particular that of the SKA (Square Kilometre Array). The design of integrated circuits for specific applications is becoming increasingly important in this field. The first step in this work is a bibliography study on integrated active reactors and their main applications dedicated to radio astronomy. This study allowed making a state of the art. This state of the art has highlighted that the integration of some functions is made especially difficult by the need to use an inductor. This is mainly due to the large size of passive inductors. These functions include the filtering function, some transceivers types, the time delay, etc. But, they are very important in radio-frequency architecture owing to phased array antennas. This thesis propose the study and design of these different functions using active inductors based on gyrators topologies in SiGeC 0.25 μm technology in order to overcome the integration problems. One of the aims of this thesis is to show that the consumption of this integration process is not so excessive for these applications, compared to the use of integrated located inductors occupying a large area on the substrate. This last point is a very important result for projects where high integration at low cost is necessary, key point of the success of dense phased array in the SKA international project.