Novel Multicarrier Memory Channel Architecture Using Microwave Interconnects: Alleviating the Memory Wall

abstract: The increase in computing power has simultaneously increased the demand for input/output (I/O) bandwidth. Unfortunately, the speed of I/O and memory interconnects have not kept pace. Thus, processor-based systems are I/O and interconnect limited. The memory aggregated bandwidth is not scaling fast enough to keep up with increasing bandwidth demands. The term "memory wall" has been coined to describe this phenomenon. A new memory bus concept that has the potential to push double data rate (DDR) memory speed to 30 Gbit/s is presented. We propose to map the conventional DDR bus to a microwave link using a multicarrier frequency division multiplexing scheme. The memory bus is formed using a microwave signal carried within a waveguide. We call this approach multicarrier memory channel architecture (MCMCA). In MCMCA, each memory signal is modulated onto an RF carrier using 64-QAM format or higher. The carriers are then routed using substrate integrated waveguide (SIW) interconnects. At the receiver, the memory signals are demodulated and then delivered to SDRAM devices. We pioneered the usage of SIW as memory channel interconnects and demonstrated that it alleviates the memory bandwidth bottleneck. We demonstrated SIW performance superiority over conventional transmission line in immunity to cross-talk and electromagnetic interference. We developed a methodology based on design of experiment (DOE) and response surface method techniques that optimizes the design of SIW interconnects and minimizes its performance fluctuations under material and manufacturing variations. Along with using SIW, we implemented a multicarrier architecture which enabled the aggregated DDR bandwidth to reach 30 Gbit/s. We developed an end-to-end system model in Simulink and demonstrated the MCMCA performance for ultra-high throughput memory channel. Experimental characterization of the new channel shows that by using judicious frequency division multiplexing, as few as one SIW interconnect is sufficient to transmit the 64 DDR bits. Overall aggregated bus data rate achieves 240 GBytes/s data transfer with EVM not exceeding 2.26% and phase error of 1.07 degree or less.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Passive and active circuits in cmos technology for rf, microwave and millimeter wave applications

The permeation of CMOS technology to radio frequencies and beyond has fuelled an urgent need for a diverse array of passive and active circuits that address the challenges of rapidly emerging wireless applications. While traditional analog based design approaches satisfy some applications, the stringent requirements of newly emerging applications cannot necessarily be addressed by existing design ideas and compel designers to pursue alternatives. One such alternative, an amalgamation of microwave and analog design techniques, is pursued in this work. A number of passive and active circuits have been designed using a combination of microwave and analog design techniques. For passives, the most crucial challenge to their CMOS implementation is identified as their large dimensions that are not compatible with CMOS technology. To address this issue, several design techniques – including multi-layered design and slow wave structures – are proposed and demonstrated through experimental results after being suitably tailored for CMOS technology. A number of novel passive structures - including a compact 10 GHz hairpin resonator, a broadband, low loss 25-35 GHz Lange coupler, a 25-35 GHz thin film microstrip (TFMS) ring hybrid, an array of 0.8 nH and 0.4 nH multi-layered high self resonant frequency (SRF) inductors are proposed, designed and experimentally verified. A number of active circuits are also designed and notable experimental results are presented. These include 3-10 GHz and DC-20 GHz distributed low noise amplifiers (LNA), a dual wideband Low noise amplifier and 15 GHz distributed voltage controlled oscillators (DVCO). Distributed amplifiers are identified as particularly effective in the development of wideband receiver front end sub-systems due to their gain flatness, excellent matching and high linearity. The most important challenge to the implementation of distributed amplifiers in CMOS RFICs is identified as the issue of their miniaturization. This problem is solved by using integrated multi-layered inductors instead of transmission lines to achieve over 90% size compression compared to earlier CMOS implementations. Finally, a dual wideband receiver front end sub-system is designed employing the miniaturized distributed amplifier with resonant loads and integrated with a double balanced Gilbert cell mixer to perform dual band operation. The receiver front end measured results show 15 dB conversion gain, and a 1-dB compression point of -4.1 dBm in the centre of band 1 (from 3.1 to 5.0 GHz) and -5.2 dBm in the centre of band 2 (from 5.8 to 8 GHz) with input return loss less than 10 dB throughout the two bands of operation

Structural and functional analysis of SynCph2(1-2), a non-canonical phytochrome from Synechocystis sp. PCC 6803

Phytochrome sind Bilin-bindende Photorezeptoren, die zwischen einer Rotlicht- (Pr) und einer Dunkelrotlicht-absorbierenden Form (Pfr) photokonvertieren können. SynCph2 aus Synechocystis sp. PCC 6803 weist einen GAF1-GAF2-GGDEF1*-EAL-GAF3-GGDEF2 Domänenaufbau auf, was darauf hindeutet, dass es sich um ein Hybrid aus einem GAF-GAF-Bidomänen-Phytochrom und einem Cyanobakteriochrom (GAF3) handelt. Diese Arbeit enthält eine detaillierte Analyse des N-terminalen GAF1-GAF2 Moduls. SynCph2(1-2) weist eine rot/dunkelrote Photochemie auf; somit ist die GAF2 Domäne in der Lage, die kanonische PHY Domäne zu ersetzen. Der Chromophor PCB ist kovalent an Cys-129 in der GAF1 Domäne gebunden. In Kooperation mit der Gruppe von P. Hildebrandt konnten wir zeigen, dass alle vier Pyrrolstickstoffe sowohl in Pr (ZZZssa) als auch in Pfr (ZZEssa) protoniert sind. In der Fern-UV CD Spektroskopie konnte ein 3%iger Anstieg des α-Helix Gehaltes in der Pr → Pfr Phototransformation festgestellt werden. Desweiteren erhöht sich in Pfr der hydrodynamische Durchmesser von SynCph2(1-2). Die Kristallstruktur von SynCph2(1-2) in der Pr Konformation konnte bei einer Auflösung von 2,6 Å gelöst werden. Das Protein kristallisiert als antiparalleles Dimer, wobei die GAF1 und GAF2 Domänen durch einen α-helikalen Linker verbunden sind. Die GAF2 Domäne ahmt den strukturellen Aufbau der kanonischen PHY Domäne nach, indem sie mit einem Zungen-ähnlichen Vorsprung die Chromophorbindungstasche in GAF2 abdeckt. Der Chromophor PCB in seiner ZZZssa Konformation ist nicht planar, sondern zeigt eine Verkippung der B-/C- sowie der C-/D-Ringe gegeneinander. Basierend auf der Kristallstruktur führten wir eine Mutagenesestudie durch, die die D-Ringumgebung und Propionatinteraktionen des Chromophors sowie die Zungenregion umfasste. Dabei unterscheiden sich die B-Ringpropionatinteraktionen von kanonischen Phytochromen und scheinen vom Typ der Effektordomäne abzuhängen. Die Analyse konservierter Motive in der Zungenregion führte zu einem Modell, das die strukturellen Änderungen während der Photokonversion beschreibt. Dabei wird die Zungenregion durch einen Trp-Positionstausch in den W(G/A)G und WxE Motiven verdreht, die als Anker die Pfr Struktur stabilisieren. Desweiteren bricht die Asp-Arg Salzbrücke, das PRxSF Motiv wird reorientiert und wahrscheinlich α-helikal, wodurch sich die neue Asp-Ser Interaktion ausbilden kann. Eine nähere Untersuchung des Photozyklus’ von SynCph2(1-2) ergab vier Intermediate in der Pr → Pfr und drei in der Pfr → Pr Photokonversion. Trotz ihrer Distanz von ~13 Å und ~15 Å zum D-Ring des Chromophors, beeinflussen Ser-385 aus dem PRxSF und Trp-389 aus dem WxE Motiv die Bildung des Pfr Zustandes. Die S385A Mutation wirkt sich auf das letzte Intermediat der Pr → Pfr Photokonversion und das erste der Rückreaktion aus. Die W389A Mutation beeinflusst schon das dritte Intermediat, das direkt in einen degenerierten Rotlicht-adaptierten Zustand zerfällt. Die drei PDeg → Pr Intermediate unterscheiden sich alle von SynCph2(1-2). Ein Austausch von Trp-389 mit Phenylalanin stellt das Wildtyp-ähnliche Verhalten wieder her. Wir schlussfolgern, dass in den ersten zwei Intermediaten nur der Chromophor und seine nächste Umgebung von Veränderungen betroffen sind. Während der Bildung von Intermediat R2 treten die strukturellen Änderungen in der Zungenregion auf, die den oben postulierten Tryptophanwechsel beinhalten. Die Bildung des letzten Intermediates leitet die Reorientierung von Ser-385 und die Ausbildung des Wasserstoffbrückennetzwerkes ein, das das Aspartat der GAF1 Domäne sowie Ser-385 einschließt. Im Rahmen einer Arbeit, die mit P. Savakis, S. De Causmaecker und V. Angerer in Kooperation mit der Gruppe von A. Wilde ausgeführt wurde, konnten wir die Rolle des C-terminalen GAF3-GGDEF2 Moduls beleuchten. SynCph2(5-6) photokonvertiert zwischen einer Blau- (Pb) und Grünlicht-absorbierenden (Pg) Form. PCB ist kovalent an Cys-1022 und Cys-994 gebunden und wird zu PVB autoisomerisiert. Das Modul ist in der Lage, lichtabhängig c-di-GMP in der GGDEF2 Domäne herzustellen, wobei der Signalzustand Pg auch in in vivo Studien in Synechocystis sp. bestätigt wurde. Unter Blaulichtbedingungen führt die c-di-GMP Herstellung von SynCph2(5-6) zu einer Inhibierung der Phototaxis. Durch Koproduktion von SynCph2(5-6) und SynCph2(1-4) konnte der Wildtypphenotyp unter Weisslicht wiederhergestellt werden, was zeigt, dass SynCph2(1-4) eine enzymatische Aktivität aufweist, die durch die c-di-GMP-abbauende EAL Domäne verursacht wird. Die hier dargelegten Studien von SynCph2 zeigen das Zusammenspiel von photochemischen und strukturellen Eigenschaften in den Pr / Pfr und Pb / Pg interkonvertierenden Modulen sowie ihre Bedeutung in vivo. Zukünftige Studien profitieren von den Einblicken in die Signaltransduktion in Phytochromen und insbesondere von der Trp-Schalterhypothese

Synthesis, design, and fabrication techniques for reconfigurable microwave and millimeter-wave filters

As wireless communication becomes increasingly ubiquitous, the need for radio receivers which can dynamically adjust to their operating environment grows more urgent. In order to realize reconfigurable receivers, tunable RF front-end components are needed. This dissertation focuses on the theory, design, and implementation of reconfigurable microwave and millimeter-wave filters for use in such receivers. First, a theoretical framework is developed for absorptive bandstop filters, a new class of bandstop filters which overcomes some of the limitations of traditional tunable bandstop filters caused by the use of lossy tunable resonators. This theory is used in conjunction with silicon-micromachining fabrication technology to realize the first ever tunable bandstop filter at W-Band frequencies, as well as a state-of-the-art Ka-band tunable bandstop filter. The problem of bandwidth variation in tunable filters is then addressed. Widely-tunable filters often suffer from variations in bandwidth, excluding them from many applications which require constant bandwidth. A new method for reducing the bandwidth variation of filters using low-loss evanescent-mode cavity resonators is presented, and this technique is used to realize up to 90% reduction of bandwidth variation in octave-tunable bandstop filters. Lastly, a new differential coupling structure for evanescent-mode cavity resonators is developed, enabling the design of fully-balanced and balanced-to-unbalanced (balun) filters. An octave-tunable 3-pole bandpass balun filter using this coupling structure is presented. The balun filter has excellent amplitude and phase balance, resulting in common-mode rejection of greater than 40 dB across its octave tuning range

Synthesis, design, and fabrication techniques for reconfigurable microwave and millimeter-wave filters

As wireless communication becomes increasingly ubiquitous, the need for radio receivers which can dynamically adjust to their operating environment grows more urgent. In order to realize reconfigurable receivers, tunable RF front-end components are needed. This dissertation focuses on the theory, design, and implementation of reconfigurable microwave and millimeter-wave filters for use in such receivers. First, a theoretical framework is developed for absorptive bandstop filters, a new class of bandstop filters which overcomes some of the limitations of traditional tunable bandstop filters caused by the use of lossy tunable resonators. This theory is used in conjunction with silicon-micromachining fabrication technology to realize the first ever tunable bandstop filter at W-Band frequencies, as well as a state-of-the-art Ka-band tunable bandstop filter. The problem of bandwidth variation in tunable filters is then addressed. Widely-tunable filters often suffer from variations in bandwidth, excluding them from many applications which require constant bandwidth. A new method for reducing the bandwidth variation of filters using low-loss evanescent-mode cavity resonators is presented, and this technique is used to realize up to 90% reduction of bandwidth variation in octave-tunable bandstop filters. Lastly, a new differential coupling structure for evanescent-mode cavity resonators is developed, enabling the design of fully-balanced and balanced-to-unbalanced (balun) filters. An octave-tunable 3-pole bandpass balun filter using this coupling structure is presented. The balun filter has excellent amplitude and phase balance, resulting in common-mode rejection of greater than 40 dB across its octave tuning range

Inverter Design for SiC-based Electric Drive Systems with Optimal Redundant States Control of Space Vector Modulation

The need for inverters with ever increasing power density and efficiency has recently become the driving factor for research in various fields. Increasing the operating voltage of the whole drive system and utilizing newly developed SiC power switches can contribute towards this goal. Higher operating voltage allows the design of drives with lower current, which leads to lower copper losses in cables and machine, while SiC switches can drastically increase the inverter efficiency. Offshore renewable power generation, such as tidal power, is a typical application where the increase of operating voltage can be highly beneficial. The ongoing electrification of transportation calls also for high power electric powertrains with high power density,where SiC technology has key advantages.In the first part of the thesis, suitable control schemes for inverters in synchronous machine drive systems are derived. A properly designed Maximum Power Point Tracking algorithm for kite-based tidal power systems is presented. The speed and torque of this new tidal power generation system varies periodically and the inverter control needs to be able to handle this variable power profile. Experimental verification of the developed control is conducted on a 35 kVA laboratory emulator of the tidal power generation unit.Electric drives using multilevel inverters are studied afterwards. Multilevel inverters use multiple low-voltage-rated switches and can operate at higher voltage than standard two-level inverters. The Neutral Point Clamped (NPC) converter is a commonly used multilevel inverter topology for medium voltage machine drives. However, the voltage balancing of its dc-side capacitors and the complexity of its control are still issues that have not been effectively solved. A new method for the optimal utilization of the redundant states in Space Vector pulse-width-Modulation (SVM) is proposed in this thesis in order to control its dc-link voltages. Experimental verification on a 4-kV-rated prototype medium-voltage PMSM drive with 5-level NPC converters is conducted in order to validate the effectiveness of the proposed control technique.Low switching and conduction losses are typical characteristics of SiC switches that can be utilized to build inverters with high power density, due to the increased efficiency and smaller form-factor. Due to the above, SiC power modules have been particularly attractive for the automotive industry. The design approach of 2-level automotive inverters has been studied in this project. Moreover, a new design approach for the cooling system of automotive inverters has been developed in this thesis, which fine-tunes the inverter heatsink utilizing standard legislated test routines for electric vehicles. Multiple conjugate-heat-transfer (CHT) computation results showcase the iterative optimization procedure on a test-case 250 kW (450 A) automotive SiC inverter.Finally, the experimental testing of high power machine drives in order to verify the control and the hardware design is an important step of the development process. Thus, the performance of the prototype 450 A SiC 2-level inverter has been been experimentally validated in a power hardware-in-the-loop (P-HIL) set-up that emulates an automotive drive system. Several challenges have been addressed with respect to the accurate modelling of the motor and the control of the circulating power in the system. A new control technique utilizing the redundant states of the SVM has been developed for this set-up to effectively suppress the zero-sequence current to 3.3 % of the line current at rated power

Development of biomedical devices for the extracorporeal real-time monitoring and perfusion of transplant organs

The goal of this Thesis is to develop a range of technologies that could enable a paradigm shift in organ preservation for renal transplantation, transitioning from static cold storage to warm normothermic blood perfusion. This transition could enable the development of novel pre-implantation therapies, and even serve as the foundation for a global donor pool. A low-hæmolysis pump was developed, based on a design first proposed by Nikola Tesla in 1913. Simulations demonstrated the theoretical superiority of this design over existing centrifugal pumps for blood recirculation, and provided insights for future avenues of research into this technology. A miniature, battery-powered, multimodal sensor suite for the in-line monitoring of a blood perfusion circuit was designed and implemented. This was named the ‘SmartPipe’, and proved capable of simultaneously monitoring temperature, pressure and blood oxygen saturations over the biologically-relevant ranges of each modality. Finally, the Thesis details the successful implementation and optimisation of a combined microfluidic and microdialysis system for the real-time quantitation of creatinine in blood or urine through amperometric sensing, to act as a live renal function monitor. The range of detection was 4.3μM – 500μM, with the possibility of extending this in both directions. This work also details and explores a novel methodology for functional monitoring in closed-loop systems which avoids the need for sensor calibration, and potentially overcomes the problems of sensor drift and desensitisation.Open Acces

Impedance Transformers

Non