RF MEMS reference oscillators platform for wireless communications

A complete platform for RF MEMS reference oscillator is built to replace bulky quartz from mobile devices, thus reducing size and cost. The design targets LTE transceivers. A low phase noise 76.8 MHz reference oscillator is designed using material temperature compensated AlN-on-silicon resonator. The thesis proposes a system combining piezoelectric resonator with low loading CMOS cross coupled series resonance oscillator to reach state-of-the-art LTE phase noise specifications. The designed resonator is a two port fundamental width extensional mode resonator. The resonator characterized by high unloaded quality factor in vacuum is designed with low temperature coefficient of frequency (TCF) using as compensation material which enhances the TCF from - 3000 ppm to 105 ppm across temperature ranges of -40˚C to 85˚C. By using a series resonant CMOS oscillator, phase noise of -123 dBc/Hz at 1 kHz, and -162 dBc/Hz at 1MHz offset is achieved. The oscillator’s integrated RMS jitter is 106 fs (10 kHz–20 MHz), consuming 850 μA, with startup time is 250μs, achieving a Figure-of-merit (FOM) of 216 dB. Electronic frequency compensation is presented to further enhance the frequency stability of the oscillator. Initial frequency offset of 8000 ppm and temperature drift errors are combined and further addressed electronically. A simple digital compensation circuitry generates a compensation word as an input to 21 bit MASH 1 -1-1 sigma delta modulator incorporated in RF LTE fractional N-PLL for frequency compensation. Temperature is sensed using low power BJT band-gap front end circuitry with 12 bit temperature to digital converter characterized by a resolution of 0.075˚C. The smart temperature sensor consumes only 4.6 μA. 700 MHz band LTE signal proved to have the stringent phase noise and frequency resolution specifications among all LTE bands. For this band, the achieved jitter value is 1.29 ps and the output frequency stability is 0.5 ppm over temperature ranges from -40˚C to 85˚C. The system is built on 32nm CMOS technology using 1.8V IO device

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

準ミリ波・ミリ波領域における低位相雑音電圧制御発振器のLC共振器に関する研究

2017岡山県立大学大学

Korkeataajuisten 65nm CMOS LC oscillaattoreiden käyttö kelojen hyvyysarvon todentamisessa

High quality factor inductors are essential for the design of low phase noise LC oscillators which play an important role in the transceivers of wireless communication devices. The reception capabilities of a radio frequency receiver are to great extent defined by the phase noise performance of the local oscillator. It is therefore important for modern single chip fully integrated transceiver design that high quality inductors are available and well modeled. In this work we investigate the possibility of evaluating the quality factor of an inductor by the phase noise it generates when used in a reference oscillator. A differential CMOS LC oscillator is designed for inductor test benching. The designed oscillator is fabricated on a 65nm CMOS process with two different inductor designs with simulated quality factors of 7.4 and 10.2. The overall combined silicon area of the two oscillators including inductors and probing pads is 680μm by 510μm. The oscillation frequencies are dictated by the designed inductors and were measured 3.04GHz and 4.56GHz. The oscillators achieve a phase noise of -125dBc/Hz and -124dBc/Hz at 1MHz offset with 14mW and 16mW power dissipation respectively. An oscillator phase noise model is fitted to the measured phase noise data of both oscillators and the model parameters are compared. The received quality factors for the designed inductors are 8.2 ± 0.8 and 10.8 ± 0.6 respectively. It was found that the measured phase noise is in good agreement with the results predicted by the model and the relative quality factor can, with certain limitations, be estimated through relative phase noise measurements

Innovative Microwave and Millimetre-Wave Components and Sub-Systems Based on Substrate Integration Technology

RÉSUMÉ Avec le rapide développement des technologies microondes et millimétriques, les spécifications de conception des circuits et systèmes sont de plus en plus exigeantes. La tendance pour le développement des systèmes de communication se dirige vers un poids minimisé, une taille réduite, de multiples fonctions, une fiabilité accrue et un faible coût. Ainsi, des technologies microondes et millimétriques faibles coûts, performantes et convenant à une production de masse sont critiques pour développer avec succès des systèmes commerciaux. La technologie à guide d’ondes rectangulaire a toujours été parmi les plus populaires pour la fabrication des systèmes millimétriques. Cependant, une difficulté majeure est reliée à leur intégration avec des composants actifs et les autres types de lignes de transmission conventionnelles, telle que microruban ou coplanaire… Les technologies de Circuits Intégrés au Substrat (CISs), incluant la technologie Guide Intégré au Substrat (GIS), qui peut être intégrée dans les substrats diélectriques avec de faibles pertes d’insertion et de radiation, sont une famille de nouvelles structures à ondes guidées. Ces dernières permettent de faire un pont entre les structures planaires et non-planaires. Jusqu’à maintenant, les composants et les sous-systèmes micro-ondes basés sur la technologie GIS ont été largement étudiés et développés. Dans cette thèse, nous étudions d’avantage la technologie GIS afin de proposer et développer divers composants actif et passif micro-ondes et millimétriques innovant et originaux. Ces structures de composants innovants peuvent améliorer l’intégration entre les composants GIS et les autres composants planaires. Ainsi, un certain nombre de structures et composants sont proposés et appliqués dans la conception et la démonstration d’un réseau d’antennes intégré en ondes millimétriques et un sous-système d’antennes intelligentes à 60 GHz. Il est à noter que plusieurs composants étudiés dans ce travail ont été proposés et démontrés à des fréquences micro-ondes plus basses afin de faire une preuve de concept en permettant une fabrication facile des structures et des circuits. Ces circuits en basses fréquences peuvent facilement être adaptés pour des applications aux fréquences plus hautes.---------- ABSTRACT The tendency of modern microwave and millimetre-wave communication system development is towards small size, light weight, reliable, multifunctional and low-cost. Moreover, low-cost, mass producible, high-performance and high-yield microwave and millimetre wave technologies are crucial for developing successful commercial microwave and millimetre wave systems. Rectangular waveguide has always been among the most popular choices for the making of millimetre-wave circuits and systems. A major challenge, however, is related to its integration with active devices and other conventional planar transmission lines, such as microstrip or coplanar waveguide (CPW), etc. Substrate Integrated Circuits (SICs) techniques including substrate integrated waveguide (SIW), which can be integrated in planar dielectric substrate with low insertion loss, high Q and low radiation loss, present a family of novel guided wave structures. This scheme provides a bridge between planar and non-planar structures. Up to now, microwave components and sub-systems based on SIW technology have been widely studied and developed. In this thesis, we take a further study of SIW technology to propose and develop various innovative and original microwave and millimetre-wave passive and active components. These innovative component structures can improve the integration between SIW components and other planar components. Then, a certain number of proposed structures or components are applied in the design and demonstration of millimetre-wave integrated antenna arrays and 60 GHz smart antenna sub-system. Note that many components studied in this work were proposed and demonstrated at different lower microwave frequencies for the proof of concept purpose with easy-to-fabricate structures and circuits. Those low-frequency circuits can easily be scaled up for high-frequency applications

Reconfigurable Receiver Front-Ends for Advanced Telecommunication Technologies

The exponential growth of converging technologies, including augmented reality, autonomous vehicles, machine-to-machine and machine-to-human interactions, biomedical and environmental sensory systems, and artificial intelligence, is driving the need for robust infrastructural systems capable of handling vast data volumes between end users and service providers. This demand has prompted a significant evolution in wireless communication, with 5G and subsequent generations requiring exponentially improved spectral and energy efficiency compared to their predecessors. Achieving this entails intricate strategies such as advanced digital modulations, broader channel bandwidths, complex spectrum sharing, and carrier aggregation scenarios. A particularly challenging aspect arises in the form of non-contiguous aggregation of up to six carrier components across the frequency range 1 (FR1). This necessitates receiver front-ends to effectively reject out-of-band (OOB) interferences while maintaining high-performance in-band (IB) operation. Reconfigurability becomes pivotal in such dynamic environments, where frequency resource allocation, signal strength, and interference levels continuously change. Software-defined radios (SDRs) and cognitive radios (CRs) emerge as solutions, with direct RF-sampling receivers offering a suitable architecture in which the frequency translation is entirely performed in digital domain to avoid analog mixing issues. Moreover, direct RF- sampling receivers facilitate spectrum observation, which is crucial to identify free zones, and detect interferences. Acoustic and distributed filters offer impressive dynamic range and sharp roll off characteristics, but their bulkiness and lack of electronic adjustment capabilities limit their practicality. Active filters, on the other hand, present opportunities for integration in advanced CMOS technology, addressing size constraints and providing versatile programmability. However, concerns about power consumption, noise generation, and linearity in active filters require careful consideration.This thesis primarily focuses on the design and implementation of a low-voltage, low-power RFFE tailored for direct sampling receivers in 5G FR1 applications. The RFFE consists of a balun low-noise amplifier (LNA), a Q-enhanced filter, and a programmable gain amplifier (PGA). The balun-LNA employs noise cancellation, current reuse, and gm boosting for wideband gain and input impedance matching. Leveraging FD-SOI technology allows for programmable gain and linearity via body biasing. The LNA's operational state ranges between high-performance and high-tolerance modes, which are apt for sensitivityand blocking tests, respectively. The Q-enhanced filter adopts noise-cancelling, current-reuse, and programmable Gm-cells to realize a fourth-order response using two resonators. The fourth-order filter response is achieved by subtracting the individual response of these resonators. Compared to cascaded and magnetically coupled fourth-order filters, this technique maintains the large dynamic range of second-order resonators. Fabricated in 22-nm FD-SOI technology, the RFFE achieves 1%-40% fractional bandwidth (FBW) adjustability from 1.7 GHz to 6.4 GHz, 4.6 dB noise figure (NF) and an OOB third-order intermodulation intercept point (IIP3) of 22 dBm. Furthermore, concerning the implementation uncertainties and potential variations of temperature and supply voltage, design margins have been considered and a hybrid calibration scheme is introduced. A combination of on-chip and off-chip calibration based on noise response is employed to effectively adjust the quality factors, Gm-cells, and resonance frequencies, ensuring desired bandpass response. To optimize and accelerate the calibration process, a reinforcement learning (RL) agent is used.Anticipating future trends, the concept of the Q-enhanced filter extends to a multiple-mode filter for 6G upper mid-band applications. Covering the frequency range from 8 to 20 GHz, this RFFE can be configured as a fourth-order dual-band filter, two bandpass filters (BPFs) with an OOB notch, or a BPF with an IB notch. In cognitive radios, the filter’s transmission zeros can be positioned with respect to the carrier frequencies of interfering signals to yield over 50 dB blocker rejection

A New and Efficient Method of Designing Low Noise Microwave Oscillators

Die Dimensionierung von Mikrowellen-Oszillatoren war und ist das Thema vieler Veröffentlichungen. Zu einem gewissen Grade wurden Oszillatoren primär aufgrund experimenteller Daten und Erfahrungen gebaut und deren Eigenschaften dann gemessen und die Daten veröffentlicht. Von der Anwenderseite her ist es jedoch wichtig und sinnvoll, dass man von einem Satz Spezifikationen ausgeht und dann eine Synthese-Prozedur hat, die zur erfolgreichen Schaltung führt. Im Rahmen dieser Dissertation wurde zunächst einmal die vorhandene internationale Literatur untersucht und dahin geprüft, welche Ansätze zum optimalen Design vorhanden sind. Hier werden die entsprechenden Literaturstellen aufgeführt und kommentiert. Einer der beliebtesten Oszillatorschaltungen ist die Colpitts-Schaltung. Diese wird im Rahmen der Dissertation genauer untersucht, wobei zunächst das Kleinsignalverhalten betrachtet wird und dann das Großsignalverhalten ausführlich dargestellt wird. Es werden Mikrowellen Bipolar-Transistoren verwendet, da sich deren Großsignalparameter stärker ändert als die von Feldeffekttransistoren. Es folgt sodann eine Darstellung des Rauschens innerhalb des Transistors. Der Kern der Arbeit stellt eine mathematische Analyse dar, die es gestattet, sowohl das Großsignalverhalten als auch das Rauschen des Oszillators zu berechnen, wobei erstmalig in der Literatur das Verhalten der Ausgangsleistung und des Rauschens des Oszillators genau betrachtet wird und für beides der beste Arbeitspunkt berechnet wurde. Um dieses zu unterstützen, wurden gleichzeitig verfügbare Resonatoren angesprochen und die Messung des Großsignalverhaltens des Transistors sowie die Messung des Phasenrauschens dargestellt. Nach der mathematischen Darstellung des Problems wurden eine Reihe von Oszillatoren nach dem Schema aufgebaut und vermessen. Es zeigt sich eine exzellente Übereinstimmung zwischen der Messung, der Synthese-Berechnung, die auch eine Analyse beinhaltet und einer vollen HB-Analyse mit einem kommerziellen Simulator. Insgesamt wurden drei Methode zur Rauschberechnung und Optimierung dargestellt. 1. Eine Erweiterung der Leeson-Formel mit exakter Berechnung aller notwendigen Parameter. 2. Die Berechnung des zur Entdämpfung notwendigen negativen Widerstandes des Oszillators im Zeitbereich unter Einbeziehung seines Rauschens. 3. Die Rausch-Berechnung des Oszillators mit allen Rauschbeiträgen des Oszillators als Regelschleifen-Problem. Die Arbeit wird abgerundet durch drei diskrete Beispiele im Anhang, bei denen die generelle Berechnung des Oszillators das Verhalten im Großsignalbereich und abschließend die Berechnung eines optimierten Oszillators mit allen parasitären Elementen durchgeführt wurde.How to design microwave oscillators has been and is the subject of many publications. To a certain degree oscillators had been designed based on experimental data and experiences and the resulting performance has been measured and published. The designer, however, considers it important and useful to start from a set of specifications and then applies a synthesis procedure, which leads to a successful circuit. Within the scope of this dissertation, the existing literature has been searched to find which successful and optimum design-procedures were published. The relevant literature is referenced and commented. One of the more favorable oscillator circuits is the Colpitts circuit. This dissertation takes a closer look at it, starting with a small signal performance and then the large signal performance is discussed in detail. Since the large signal parameters deviate further from the small signal parameters, microwave bipolar transistors are being used rather than field-effect transistors. Next is a discussion of the noise of a transistor. The core of the work is a mathematical analysis, which allows to calculate both large signal performance and noise performance whereby as a first the output power and the noise are simultaneously considered and the optimum bias point is found. In order to support this, various resonators are discussed. The measurement of large signal parameters of the transistor is shown and finally phase noise measurements are presented. Following the mathematical solution of the problem, various oscillators had been built following this procedure and were measured. There is an excellent agreement between measurement and this synthesis calculation, which also contains an analysis. An excellent agreement is also found using a HB-based commercial simulator. In total three methods to calculate the phase noise and obtain best performance are demonstrated. 1.An extension of the Leeson formula with exact calculation of all necessary parameters. 2.The calculation of the negative noisy resistance necessary to start oscillation is calculated in time domain. 3.Noise calculation of an oscillator including all noises as a loop problem. This work finishes by showing three discrete cases in the appendix. Here the oscillators general performance is calculated using large signal conditions and finally an optimized oscillator with all parasitic elements is shown