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CMOS design enhancement techniques for RF receivers. Analysis, design and implementation of RF receivers with component enhancement and component reduction for improved sensitivity and reduced cost, using CMOS technology.
Silicon CMOS Technology is now the preferred process for low power wireless
communication devices, although currently much noisier and slower than comparable
processes such as SiGe Bipolar and GaAs technologies. However, due to ever-reducing
gate sizes and correspondingly higher speeds, higher Ft CMOS processes are
increasingly competitive, especially in low power wireless systems such as Bluetooth,
Wireless USB, Wimax, Zigbee and W-CDMA transceivers. With the current 32 nm gate
sized devices, speeds of 100 GHz and beyond are well within the horizon for CMOS
technology, but at a reduced operational voltage, even with thicker gate oxides as
compensation.
This thesis investigates newer techniques, both from a systems point of view and at a
circuit level, to implement an efficient transceiver design that will produce a more
sensitive receiver, overcoming the noise disadvantage of using CMOS Silicon. As a
starting point, the overall components and available SoC were investigated, together
with their architecture.
Two novel techniques were developed during this investigation. The first was a high
compression point LNA design giving a lower overall systems noise figure for the
receiver. The second was an innovative means of matching circuits with low Q
components, which enabled the use of smaller inductors and reduced the attenuation
loss of the components, the resulting smaller circuit die size leading to smaller and
lower cost commercial radio equipment. Both these techniques have had patents filed by the
University.
Finally, the overall design was laid out for fabrication, taking into account package
constraints and bond-wire effects and other parasitic EMC effects
Muon g-2 and lepton flavor violation in a two Higgs doublets model for the fourth generation
In the minimal Standard Model (SM) with four generations (the so called SM4)
and in "standard" two Higgs doublets model (2HDM) setups, e.g., the type II
2HDM with four fermion generations, the contribution of the 4th family heavy
leptons to the muon magnetic moment is suppressed and cannot accommodate the
measured access with respect to the SM prediction. We show
that in a 2HDM for the 4th generation (the 4G2HDM), which we view as a low
energy effective theory for dynamical electroweak symmetry breaking, with one
of the Higgs doublets coupling only to the 4th family leptons and quarks (thus
effectively addressing their large masses), the loop exchanges of the heavy 4th
generation neutrino can account for the measured value of the muon anomalous
magnetic moment. We also discuss the sensitivity of the lepton flavor violating
decays and and of the decay to the new couplings which control the muon g-2 in our model.Comment: v1: 13 pages, 11 figure
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
CMOS design enhancement techniques for RF receivers : analysis, design and implementation of RF receivers with component enhancement and component reduction for improved sensitivity and reduced cost, using CMOS technology
Silicon CMOS Technology is now the preferred process for low power wireless communication devices, although currently much noisier and slower than comparable processes such as SiGe Bipolar and GaAs technologies. However, due to ever-reducing gate sizes and correspondingly higher speeds, higher Ft CMOS processes are increasingly competitive, especially in low power wireless systems such as Bluetooth, Wireless USB, Wimax, Zigbee and W-CDMA transceivers. With the current 32 nm gate sized devices, speeds of 100 GHz and beyond are well within the horizon for CMOS technology, but at a reduced operational voltage, even with thicker gate oxides as compensation. This thesis investigates newer techniques, both from a systems point of view and at a circuit level, to implement an efficient transceiver design that will produce a more sensitive receiver, overcoming the noise disadvantage of using CMOS Silicon. As a starting point, the overall components and available SoC were investigated, together with their architecture. Two novel techniques were developed during this investigation. The first was a high compression point LNA design giving a lower overall systems noise figure for the receiver. The second was an innovative means of matching circuits with low Q components, which enabled the use of smaller inductors and reduced the attenuation loss of the components, the resulting smaller circuit die size leading to smaller and lower cost commercial radio equipment. Both these techniques have had patents filed by the University. Finally, the overall design was laid out for fabrication, taking into account package constraints and bond-wire effects and other parasitic EMC effects.EThOS - Electronic Theses Online ServiceGBUnited Kingdo