Extension of 0.18µm standard CMOS technology operating range to the microwave and millimetre-wave regime

There is an increasing interest in building millimetre-wave circuits on standard digital complementary metal oxide semiconductor (CMOS) technology for applications such as wireless local area networks (WLAN), automotive radar and remote sensing. This stems from the existing low cost, well-developed, high yield infrastructure for mass production. The overall aim of this thesis is to extend the operating range of 0.18um standard logic CMOS technology to millimetre-wave regime. To this end, microwave and millimetre-wave design, optimisation and modelling methodologies for active and passive devices and low noise circuit implementation are described. As part of the evaluation, new systematic and modular ways of making high performance passive and active devices such as spiral inductors, slow-wave coplanar waveguide (CPW) transmission lines, comb capacitors and NMOS transistors are proposed, designed, simulated, fabricated, modelled and analysed. Small-signal and noise de-embedding techniques are developed and verified up to 110 GHz, providing an increased accuracy in the device model, leading to a robust design at millimetre-wave frequencies. Reduced substrate losses resulting in increased quality factor are presented for optimised spiral inductor designs, featuring patterned floating shield (PFS), enabling improved matching network and a reduced chip area. Based on the proposed shielded slow-wave CPW, both the line attenuation and structure length are decreased, resulting in a more compact and simplified circuit design. An optimised transistor design, aimed at reducing the layout parasitic effects, was realised. The optimisation led to a significant improvement in the gain and noise performance of the transistor, extending its operation beyond the cut-off frequency (ft). By combining all the optimised components, low noise amplifiers (LNAs) operating at 25 GHz and 40 GHz were implemented and compared. These LNAs demonstrate state-of-the-art performance, with the 40 GHz LNA exhibiting the highest gain and lowest noise performance of any LNA reported using 0.18um CMOS technology. On the other hand, the 25 GHz LNA showed a comparable performance to other reported results in literature using several topologies implemented in CMOS technology. These findings will provide a framework for expansion to smaller CMOS technology nodes with the view of extending to sub millimetre-wave frequencies

Networking chemical robots for reaction multitasking

The development of the internet of things has led to an explosion in the number of networked devices capable of control and computing. However, whilst common place in remote sensing, these approaches have not impacted chemistry due to difficulty in developing systems flexible enough for experimental data collection. Herein we present a simple and affordable (<$500) chemistry capable robot built with a standard set of hardware and software protocols that can be networked to coordinate many chemical experiments in real time. We demonstrate how multiple processes can be done with two internet connected robots collaboratively, exploring a set of azo-coupling reactions in a fraction of time needed for a single robot, as well as encoding and decoding information into a network of oscillating reactions. The system can also be used to assess the reproducibility of chemical reactions and discover new reaction outcomes using game playing to explore a chemical space

Conditioned Medium from Bone Marrow Mesenchymal Stem Cells Restored Oxidative Stress-Related Impaired Osteogenic Differentiation

Oxidative stress from high levels of intracellular reactive oxygen species (ROS) has been linked to various bone diseases. Previous studies indicate that mesenchymal stem cells (MSC) secrete bioactive factors (conditioned medium (MSC-CM)) that have antioxidant effects. However, the antioxidant role of MSC-CM on osteogenesis has not been fully studied. We aimed to identify antioxidant proteins in MSC-CM using mass spectrometry-based proteomics and to explore their effects on osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSC) exposed to oxidative stress induced by hydrogen peroxide (H2O2). Our analysis revealed that MSC-CM is comprised of antioxidant proteins that are involved in several biological processes, including negative regulation of apoptosis and positive regulation of cell proliferation. Then, hBMSC exposed to H2O2 were treated with MSC-CM, and the effects on their osteogenic differentiation were evaluated. MSC-CM restored H2O2-induced damage to hBMSC by increasing the antioxidant enzyme-SOD production and the mRNA expression level of the anti-apoptotic BCL-2. A decrease in ROS production and cellular apoptosis was also shown. MSC-CM also modulated mRNA expression levels of osteogenesis-related genes, runt-related transcription factor 2, collagen type I, bone morphogenic protein 2, and osteopontin. Furthermore, collagen type I protein secretion, alkaline phosphatase activity, and in vitro mineralization were increased. These results indicate that MSC-CM contains several proteins with antioxidant and anti-apoptotic properties that restored the impaired hBMSC osteogenic differentiation associated with oxidative stress.publishedVersio

RF and microwave oscillator design using p-HEMT transistor

This paper presents a systematic approach to designing negative-resistance and Colpitts oscillators using p-HEMT transistor. Various models such as, common source and common gate configuration in negative-resistance oscillators, common source series feedback in Colpitts oscillator is selected to analyze the output power and stability presented by the p-HEMT transistor. These oscillators are designed at 2.45 GHz frequency for which we find application in Bluetooth and Wi-Fi. In this paper, these designs are studied and tested, with their results analyzed below. Further, study proved that the Colpitts oscillator designed gave more output power and stability than the negativeresistance oscillators

RF operation of hydrogen-terminated diamond field effect transistors : a comparative study

Three sets of different gate-length field-effect transistors (250, 120, and 50 nm) have been defined on homoepitaxial hydrogen-terminated diamond with the 50-nm device being the smallest gate length diamond transistor fabricated to date. DC- and small-signal RF measurements were undertaken to compare the operation of these gate nodes. RF small-signal equivalent circuits were generated to contrast individual components and better understand the operation at various gate dimensions. Scaling the gate length to smaller dimensions leads to an increase in the cutoff frequency of these devices although parasitic elements are found to dominate at the shortest gate length of 50 nm, limiting the outstanding potential of these devices

Towards 2001 Ethnic minorities and the Census

SIGLEAvailable from British Library Document Supply Centre-DSC:f99/2333 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Recent Progress and Future Challenges in Hydrogen-Terminated Diamond Field Effect Transistor Technology

No abstract available

Recent Advances in Hydrogen-terminated Diamond FET Technology

No abstract available

Networking Chemical Robots Using Twitter for #RealTimeChem

Herein we present a chemistry capable robot built with a standard set of hardware and software protocols that can be networked to coordinate many chemical experiments in real time, such that the different chemical reactions can be distributed over many sites simultaneously. We demonstrate how multiple chemical processes can be done with two internet connected robots collaboratively, exploring a set of azo-coupling reactions in a fraction of time needed for a single robot, as well as encoding and decoding information into a network of oscillating BZ reactions transferring a message between two different locations using chemical reactions. The system can also be used to assess the reproducibility of chemical reactions and discover new reaction outcomes using game playing to explore a list of reaction conditions not accessible when the robots instead take it in turn to each a pre-define reaction from a list.</p

A Portable 3D-Printed Platform for Point-of-Care Diagnosis of Clostridium Difficile Infection and Malaria

Here, we integrate 3D-printing technology with low-cost open source electronics to develop a portable diagnostic platform suitable for a wide variety of diagnostic and sensing assays. We demonstrate two different clinical applications in the diagnosis of Clostridium difficile infection and malaria