Design of Integrated Millimeter Wave Microstrip Pseudo-Interdigital Band pass Filter Using 0.18μm CMOS Technology

High selectivity design of an improved on-chip band pass filter for 60 GHz millimeter-wave applications using0.18 μm CMOS technology is presented. A new type of miniaturized microstrip bandpass filters with pseudo- interdigital structure without via holes grounded resonators is described. A very compact filter of this type, having a size less than quarter-wavelength by quarter-wavelength at a mid-band frequency of 60 GHz was designed. The adoption of a pseudo- interdigital BPF and utilization of two transmissions zero permits a compact size and high selectivity for the BPF. Besides, two defected ground structure cells are etched under the coupled lines to improve the filter insertion loss. The proposed BPF has the center frequency of 60 GHz, insertion loss of -3.6. dB, a 3dB band width of 8 GHz, and core size 200×500 μm2 with total chip size 500×300 μm2 (including bonding pad

Contribution à la mise en oeuvre de synthèse de filtres accordables simultanément en fréquence et bande passante : application aux fréquences millimétriques et submillimétriques en technologie BiCMOS

Le but de la thèse est de réaliser des filtres accordable en technologie planaire multi-niveaux proposé par l'entreprise allemande IHP. Les filtres sont réalisés aux ondes millimétriques,principalement autour de 60 GHz et 140 GHz. Nous étudions l'accordabilité en fréquence mais aussi l'accordabilité en bande passante ne utilisant un concept nouveau établie au cours de cette thèse. Les premiers résultats concernant les filtres accordables en fréquence ont permit la rédaction de plusieurs articles. Maintenant, nous venons de recevoir les mesures prouvant notre nouveau concept permettant l'accord en fréquence et en bande passante des filtres planaires à base de résonateurs en annea

Analysis and design of wideband voltage controlled oscillators using self-oscillating active inductors.

Voltage controlled oscillators (VCOs) are essential components of RF circuits used in transmitters and receivers as sources of carrier waves with variable frequencies. This, together with a rapid development of microelectronic circuits, led to an extensive research on integrated implementations of the oscillator circuits. One of the known approaches to oscillator design employs resonators with active inductors electronic circuits simulating the behavior of passive inductors using only transistors and capacitors. Such resonators occupy only a fraction of the silicon area necessary for a passive inductor, and thus allow to use chip area more eectively. The downsides of the active inductor approach include: power consumption and noise introduced by transistors. This thesis presents a new approach to active inductor oscillator design using selfoscillating active inductor circuits. The instability necessary to start oscillations is provided by the use of a passive RC network rather than a power consuming external circuit employed in the standard oscillator approach. As a result, total power consumption of the oscillator is improved. Although, some of the active inductors with RC circuits has been reported in the literature, there has been no attempt to utilise this technique in wideband voltage controlled oscillator design. For this reason, the dissertation presents a thorough investigation of self-oscillating active inductor circuits, providing a new set of design rules and related trade-os. This includes: a complete small signal model of the oscillator, sensitivity analysis, large signal behavior of the circuit and phase noise model. The presented theory is conrmed by extensive simulations of wideband CMOS VCO circuit for various temperatures and process variations. The obtained results prove that active inductor oscillator performance is obtained without the use of standard active compensation circuits. Finally, the concept of self-oscillating active inductor has been employed to simple and fast OOK (On-Off Keying) transmitter showing energy eciency comparable to the state of the art implementations reported in the literature

CMOS-MEMS Scanning Microwave Microscopy

This thesis presents the design, fabrication and experimental validation of an integrated dual-mode scanning microwave microscopy (SMM)/Atomic Force Microscopy (AFM) system that does not require the use of a conventional laser-based AFM or external scanners. Microfabricated SMM probes are collocated with strain-based piezoresistive AFM probes in a CMOS-MEMS process, and are actuated by integrated electrothermal scanners. Integration of AFM enables dual-mode imaging (topography and electrical properties); it also enables control over tip-sample distance, which is crucial for accurate SMM imaging. The SMM (also known as Scanning Near-field Microwave Microscope and Scanning Evanescent Microwave Microscope) is the most well-known type of Scanning Probe Microscopes (SPM) that can quantify local dielectric and conductivity of materials. It has emerged as the most promising means for the fast, non-contact, and non-destructive study of materials and semiconductor devices. The CMOS-MEMS SMM devices are fabricated by using a standard foundry CMOS process, followed by an in-house mask-less post-processing technique to release them. Single-chip SMM/AFM devices with integrated 1-D and 3-D actuation are introduced. The CMOS-MEMS fabrication process allows external bulky scanners to be replaced with integrated MEMS actuators that are small and immune to vibration and drift. In this work, electrothermal MEMS actuators are utilized to scan the tip over the sample in 3 degrees of freedom, over a 13 µm x 13 µm x 10 µm scan range in the x, y, and z directions, respectively. Furthermore, the availability of polysilicon layers on the CMOS processes allows for on-chip integrated piezoresistive position sensing that obviates the need for the laser system. Vertical tip-sample distance control of a few nanometers is achieved with the integrated piezoresistive position sensors. These devices are used to modulate the tip-sample separation to underlying samples with a periodic signal, improving immunity to long-term system drifts. To improve the sensitivity of the CMOS-MEMS SMM, different types of matching networks for SMMs are thoroughly analyzed and closed form formulas are presented for each type. Based on the analyses, the stub matching method is selected to match the high tip-to-sample impedance to the 50 ohm characteristic impedance of the system. After that, with the help of lumped models and EM simulations, different sections of the CMOS-MEMS SMM system are analyzed and suggestions for selecting the best micro-transmission line and bonding-pad transmission lines are given. A measurement circuit for SMM is then presented and explained, showing how this measurement system can improve the output-signal-to-noise ratio and hence the sensitivity of microwave imaging. Calculations for the entire SMM system indicate that sub-attofarad tip-sample impedance can be measured. It is noteworthy that most of the analyses and suggestions given in this thesis can be applied to any Scanning Microwave Microscopes or, even more generally, to any microwave system that needs to sense a small signal. Finally, the measurement results for the fabricated CMOS-MEMS SMM are presented to verify the proposed methods. Several samples with sub-micron and nanometer feature sizes are imaged. A special test sample with no topography but with buried dielectric materials in grid and stripes is also designed and measured

Copper / low-k technological platform for the fabrication of high quality factor above-IC passive devices

Modern communication devices demand challenging specifications in terms of miniaturization, performance, power consumption and cost. Every new generation of radio frequency integrated circuits (RF-ICs) offer better functionality at reduced size, power consumption and cost per device and per integrated function. Passive devices (resistors, inductors, capacitors, antennas and transmission lines) represent an important part of the cost and size of RF circuits. These components have not evolved at the same level of the transistor devices, especially because their performance is strongly degenerated when they scale down in size. The low resistivity silicon used to build the transistors also imposes prohibitive levels of RF losses to these passive devices. Radio frequency microelectromechanical systems (RF MEMS) are enabling technologies capable to bring significant improvement in the electrical performances and expressive size and cost reduction of these functions, with unparallel introduction of new functionalities, unimaginable to attain when using bulky, externally connected discrete components. High quality factor (Q) inductors are amongst ones of the most needed components in RF circuits and at the same time ones that are most affected by thin metallization and substrate related losses, demanding considerable research effort. This thesis presents a contribution toward the development of thick metal fabrication technologies, covering also the design, modeling and characterization of high quality factor and high self-resonant frequency (SRF) RF MEMS passive devices, with a special emphasis on spiral inductors. A new approach using damascene-like interconnect fabrication steps associated to low κ dielectrics (polyimide), highly-conductive thick copper electroplating, chemical mechanical polishing (CMP) and tailored substrate properties delivered quality factors in excess of 40 and self resonant frequencies in excess of 10 GHz, performances in the current state-of-the-art for integrated spiral inductors built on top of silicon wafers. Furthermore, the developed process steps are compatible with back-end processing used to fabricate modern IC interconnects and have a low thermal budget (< 250 °C), what makes it a good choice to build above-IC passives without degenerating the performance of passivated RF-CMOS circuits. Deep reactive ion etching (DRIE) of quartz substrates was also studied for the fabrication of spiral inductors, offering excellent RF performances (Q exceeding 40 and SRF exceeding 7 GHz). A new doubly-functional quartz packaging concept for RF MEMS devices was developed. This technique process both sides of the packaging wafer: the top is used to embed high quality factor copper inductors while the bottom is thermo-mechanically bonded to another RF MEMS wafer, offering a semi-hermetic SU-8 epoxy-based seal. The bonding process was optimized for high yield, to be compatible with SF6-plasma-released MEMS and to present low level of RF losses. Band pass filters for the GSM (1.8 GHz) and WLAN (5.2 GHz) standards were fabricated and characterized by RF measurements and full wave electromagnetic simulations. Although further development is need in order to predict the frequency response accurately, insertion losses as low as 1.2 dB were demonstrated, levels that cannot be usually attained using on-chip passives. Systematic analysis, RF measurements, electromagnetic simulations and equivalent circuit extraction were used to model the behavior of the fabricated devices and establish a methodology to deliver optimum performances for a given technological profile and specified performance targets (quality factor, inductance and frequency bandwidth). A simple yet accurate physics-based analytical model for spiral inductors was developed and proved to be accurate in terms of loss estimation for thick metal layers. This model is capable to accurately describe the frequency-dependent behavior of the device below its first resonant frequency over a large device design space. The model was validated by both measurements and full wave electromagnetic simulations and is well suited to perform numeric optimization of designs. The proposed models were also systematized in a Matlab® toolbox

Advanced Trends in Wireless Communications

Physical limitations on wireless communication channels impose huge challenges to reliable communication. Bandwidth limitations, propagation loss, noise and interference make the wireless channel a narrow pipe that does not readily accommodate rapid flow of data. Thus, researches aim to design systems that are suitable to operate in such channels, in order to have high performance quality of service. Also, the mobility of the communication systems requires further investigations to reduce the complexity and the power consumption of the receiver. This book aims to provide highlights of the current research in the field of wireless communications. The subjects discussed are very valuable to communication researchers rather than researchers in the wireless related areas. The book chapters cover a wide range of wireless communication topics

Integrated RF oscillators and LO signal generation circuits

This thesis deals with fully integrated LC oscillators and local oscillator (LO) signal generation circuits. In communication systems a good-quality LO signal for up- and down-conversion in transmitters is needed. The LO signal needs to span the required frequency range and have good frequency stability and low phase noise. Furthermore, most modern systems require accurate quadrature (IQ) LO signals. This thesis tackles these challenges by presenting a detailed study of LC oscillators, monolithic elements for good-quality LC resonators, and circuits for IQ-signal generation and for frequency conversion, as well as many experimental circuits. Monolithic coils and variable capacitors are essential, and this thesis deals with good structures of these devices and their proper modeling. As experimental test devices, over forty monolithic inductors and thirty varactors have been implemented, measured and modeled. Actively synthesized reactive elements were studied as replacements for these passive devices. At first glance these circuits show promising characteristics, but closer noise and nonlinearity analysis reveals that these circuits suffer from high noise levels and a small dynamic range. Nine circuit implementations with various actively synthesized variable capacitors were done. Quadrature signal generation can be performed with three different methods, and these are analyzed in the thesis. Frequency conversion circuits are used for alleviating coupling problems or to expand the number of frequency bands covered. The thesis includes an analysis of single-sideband mixing, frequency dividers, and frequency multipliers, which are used to perform the four basic arithmetical operations for the frequency tone. Two design cases are presented. The first one is a single-sideband mixing method for the generation of WiMedia UWB LO-signals, and the second one is a frequency conversion unit for a digital period synthesizer. The last part of the thesis presents five research projects. In the first one a temperature-compensated GaAs MESFET VCO was developed. The second one deals with circuit and device development for an experimental-level BiCMOS process. A cable-modem RF tuner IC using a SiGe process was developed in the third project, and a CMOS flip-chip VCO module in the fourth one. Finally, two frequency synthesizers for UWB radios are presented

RF micro-electro-mechanical devices for 0.8-2.5 GHz applications in mobile terminals

This thesis presents a wide tuning range micro-electro-mechanical (MEM) capacitor. The two-gap MEM capacitor has a measured nominal capacitance of 1.58 pF and achieves a tuning range of 2.25:1 with parasitic capacitance. When all parasitic capacitance to the substrate are extracted the measured nominal capacitance is 1.15 pF and the tuning range is 2.71:1. The device is made of electroplated gold and has a Q of 66 at 1 GHz, and 53 at 2 GHz. In addition, a novel three-state capacitor is presented. Measured capacitance of the first, the second and the third state are 0.86 pF, 1.61 pF and 3.68 pF, respectively. A novel temperature-compensated two-state microelectromechanical (MEM) capacitor is presented. The principle to minimize temperature dependence is based on geometrical compensation and can be extended to other devices such as continuously tunable MEM capacitors. The compensation structure eliminates the effect of intrinsic and thermal stress on the device operation. This leads to a temperature-stable device without compromising the quality factor (Q) or the voltage behavior. The compensation structure increases the robustness of the devices, but does not require any modifications to the process. Measurement results verify that the OFF and ON capacitance change is less than 6 % and the pull-in voltage is less than 5 % when the temperature is varied from −30 °C to +70 °C. In addition to the temperature stability, the charging of the dielectric layer is studied and a new continuous reliability measurement set-up is presented. This thesis describes important design principles of electrostatically actuated MEM capacitors. Key design principles, such as temperature compensation, calculation of mechanical properties, and calculation of electrical properties of MEM capacitor are studied in detail. A new design principle that describes how pull-in and release voltage ratio is only dependent on up and down capacitance ratio and not on the mechanical properties such as a spring constant is also derived. In addition, it is shown how the RF signal affects the voltage behavior of the MEM capacitor. Two-state, three-state and continuously tunable MEM capacitors are designed and fabricated using presented design principles. Modeling, fabrication and analysis of a truly three-dimensional high-quality-factor toroidal inductor using polymer replication processes is presented. The critical dimensions are in the micrometer range, and the applied manufacturing method is based on the polymer replication. Electrical measurements show that the inductor with an inductance of 6.0 nH exhibits a Q of 37 at 1 GHz and a peak quality factor of 50 at a frequency of 3 GHz. Furthermore, the applied manufacturing technique can be extended to become a flexible packaging platform.reviewe