30 research outputs found
Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study
Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28â2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65â3·22], p\textless0·0001), American Society of Anesthesiologists grades 3â5 versus grades 1â2 (2·35 [1·57â3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01â2·39], p=0·046), emergency versus elective surgery (1·67 [1·06â2·63], p=0·026), and major versus minor surgery (1·52 [1·01â2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
Timing of surgery following SARS-CoV-2 infection: an international prospective cohort study.
Peri-operative SARS-CoV-2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS-CoV-2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre-operative SARS-CoV-2 infection were compared with those without previous SARS-CoV-2 infection. The primary outcome measure was 30-day postoperative mortality. Logistic regression models were used to calculate adjusted 30-day mortality rates stratified by time from diagnosis of SARS-CoV-2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre-operative SARS-CoV-2 diagnosis. Adjusted 30-day mortality in patients without SARS-CoV-2 infection was 1.5% (95%CI 1.4-1.5). In patients with a pre-operative SARS-CoV-2 diagnosis, mortality was increased in patients having surgery within 0-2Â weeks, 3-4Â weeks and 5-6Â weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3-4.8), 3.9 (2.6-5.1) and 3.6 (2.0-5.2), respectively). Surgery performed â„Â 7Â weeks after SARS-CoV-2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9-2.1)). After a â„Â 7Â week delay in undertaking surgery following SARS-CoV-2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2-8.7) vs. 2.4% (95%CI 1.4-3.4) vs. 1.3% (95%CI 0.6-2.0), respectively). Where possible, surgery should be delayed for at least 7Â weeks following SARS-CoV-2 infection. Patients with ongoing symptoms â„Â 7Â weeks from diagnosis may benefit from further delay
Outils de conception pour l'amplification distribuée ultra large bande aux fréquences millimétriques
Over the last few years, both data center and network traffic increased by several folds (more than six-folds, as stated by CISCO Systems, Inc.) and are still experiencing an ongoing growth. This demand for higher capacity while meeting with higher end-to-end quality service projects a continuous need for improvements in spectral efficiency enhancement techniques; however, a given spectrum band has its limit of volume it can support before reaching saturation levels. This pushes research efforts towards finding other solutions and a promising one is by exploiting the uncrowded millimeter-wave (mm-wave) spectrum through arranging more bandwidth. Signal amplification is one of the most basic and prevalent circuit function in modern RF- and microwave- systems. On the topic of wideband operation, distributed amplifier (DA) has proved to be a suitable and promising candidate with its ultra-wideband (UWB) performance. Meanwhile, the design of integrated circuit (IC) in mm-wave spectrum is becoming a challenging process due to the unavoidable parasitic that affect circuit performance and complicate design process. The reliability of the conventional design techniques through deriving mathematical equations, a simple and direct design process commonly used at low frequencies, starts to diminish. Another proposed design technique is by combining advanced-scripting languages with a proper physical model; this will lead to a smart and efficient technique of designing mm-wave IC DAs through a process referred as computer-automated design (CAutoD) process. In this thesis, in particular, we propose a novel ABCD-parameter based chain matrix model, which is more famously used in describing and designing passive circuitry. The design technique is considered complete, since its model takes into account all DA design parameters; simple, since the designer does not have to deal with the tiny effects (parasitic) that affect DA behavior; versatile, since it does not impose restrictions on the component topologies the designer might be interested to used; and finally, reliable, a crucial criterion for mm-wave design, since model does not apply simplification or neglect parasitic effects. Our end-goal is to offer the designer a different and interesting technique in which the outcome of the suggested CAutoD process is a set of 3D graphical design exploration (DSE) plots. Designers then can explore different possible solutions and choose the best design that meet their multiple performance objectives. Its benefit is demonstrated by exploring the design space of DAs with BWs â„ 80 GHz where STMicroelectronics (ST) 55-nm CMOS process, accessible through the framework of European TARANTO project, is used, reporting 216 feasible DA options to explore from. Two global optimum DAs amplifying frequencies up to 100 GHz were then implemented as circuit prototypes. A single stage DA showing with 6.01 GHz/mW of gain-bandwidth product over DC consumption (GBPâPDC ) is measured and a 17.5 THz GBP cascaded DA with 71.96 GHz/mW of GBPâPDC is proposed, being the highest figure of merits, to the authorsâ knowledge.Ces cinq derniĂšres annĂ©es, lâintensitĂ© du trafic au sein des centres et des rĂ©seaux de donnĂ©es a Ă©tĂ© multipliĂ©e par plus de six (donnĂ©es CISCO) et la tendance va en sâaccentuant. Cette demande pour une plus grande capacitĂ© de stockage et de traitement va de pair avec une qualitĂ© accrue du service aux utilisateurs, entrainant une saturation des bandes de frĂ©quences allouĂ©es aux tĂ©lĂ©communications civiles malgrĂ© les efforts dĂ©ployĂ©s pour amĂ©liorer lâefficacitĂ© spectrale. Dâautres solutions sont Ă©galement Ă©tudiĂ©es pour transmettre des signaux ultra large bande, dont lâexploitation des bandes millimĂ©triques encore peu encombrĂ©es. Dans ce contexte des transmissions radiofrĂ©quences et microondes, lâamplification du signal est une fonction basique qui prĂ©vaut sur lâensemble de la chaĂźne : entrĂ©e, sortie, rĂ©amplification en cours de propagation. Aussi, cette thĂšse sâintĂ©resse-tâelle Ă lâamplification trĂšs large bande dans le domaine du millimĂ©trique, lâamplificateur distribuĂ© sâavĂ©rant ĂȘtre le plus adĂ©quat et le plus performant parmi tous les candidats potentiels. Toutefois, sa conception nâest pas aisĂ©e. En effet, concevoir un circuit intĂ©grĂ© est une gageure en millimĂ©trique du fait des nombreux Ă©lĂ©ments parasites inhĂ©rents aux nĆuds technologiques avancĂ©s considĂ©rĂ©s et Ă la montĂ©e en frĂ©quence. Les mĂ©thodes de conception analytiques traditionnelles, performante aux basses frĂ©quences, perdent en robustesse au-delĂ de 30 GHz. Nous proposons dans cette Ă©tude une mĂ©thodologie de conception simple et efficace, dite CautoD pour Computer Automated Design, basĂ©e sur lâĂ©laboration dâun modĂšle physique du circuit et le recours Ă des algorithmes Ă©voluĂ©s adaptĂ©s au domaine radiofrĂ©quences. Notamment, nous proposons de modĂ©liser les relations entrĂ©e-sortie du DA sous la forme dâune matrice chaine de type ABCD quatre ports, ce qui nâa jamais Ă©tĂ© Ă©tudiĂ© jusquâĂ prĂ©sent pour dĂ©crire le comportement de circuits actifs. La mĂ©thode de conception considĂ©rĂ©e est complĂšte car le modĂšle tient compte de tous les paramĂštres actifs, parasites et passifs du DA ; simple car le concepteur nâa plus Ă tergiverser avec les effets secondaires qui impactent le comportement du circuit ; versatile car la mĂ©thode nâimpose aucune condition quant au choix de topologie ou de technologie du DA ; robuste malgrĂ© les frĂ©quences millimĂ©triques car lâensemble des effets parasites a Ă©tĂ© considĂ©rĂ© pour chacun des blocs Ă©lĂ©mentaires descriptifs du DA. Notre objectif, contrairement aux approches analytiques qui supposent des simplifications excessives, est dâexplorer lâespace de conception sous forme graphique de façon Ă ne conserver que les solutions sâapprochant au mieux du cahier des charges initial. LâintĂ©rĂȘt de notre outil est mis en exergue par lâexploration de lâespace de conception dâamplificateurs distribuĂ©s, de bande passante supĂ©rieure Ă 80 GHz, conçus en technologie STMicroelectronics CMOS 55-nm, accessible dans le cadre du projet europĂ©en TARANTO. Parmi les 216 options disponibles deux ont Ă©tĂ© implĂ©mentĂ©es permettant dâamplifier les frĂ©quences jusquâĂ une centaine de gigahertz. Un DA simple Ă©tage avec 6,01 GHz/mW de produit gain-bande (GBP) rapportĂ© par milliwatt de puissance consommĂ© (GBP/Pdc) a Ă©tĂ© mesurĂ© et un DA cascadĂ© de 17,5 THz de GBP est proposĂ© avec 71.96 GHz/mW of GBP/Pdc. DâaprĂšs nos sources, ce sont les plus forts facteurs de mĂ©rite reportĂ©s jusquâĂ prĂ©sent
Outils de conception pour l'amplification distribuée ultra large bande aux fréquences millimétriques
Over the last few years, both data center and network traffic increased by several folds (more than six-folds, as stated by CISCO Systems, Inc.) and are still experiencing an ongoing growth. This demand for higher capacity while meeting with higher end-to-end quality service projects a continuous need for improvements in spectral efficiency enhancement techniques; however, a given spectrum band has its limit of volume it can support before reaching saturation levels. This pushes research efforts towards finding other solutions and a promising one is by exploiting the uncrowded millimeter-wave (mm-wave) spectrum through arranging more bandwidth. Signal amplification is one of the most basic and prevalent circuit function in modern RF- and microwave- systems. On the topic of wideband operation, distributed amplifier (DA) has proved to be a suitable and promising candidate with its ultra-wideband (UWB) performance. Meanwhile, the design of integrated circuit (IC) in mm-wave spectrum is becoming a challenging process due to the unavoidable parasitic that affect circuit performance and complicate design process. The reliability of the conventional design techniques through deriving mathematical equations, a simple and direct design process commonly used at low frequencies, starts to diminish. Another proposed design technique is by combining advanced-scripting languages with a proper physical model; this will lead to a smart and efficient technique of designing mm-wave IC DAs through a process referred as computer-automated design (CAutoD) process. In this thesis, in particular, we propose a novel ABCD-parameter based chain matrix model, which is more famously used in describing and designing passive circuitry. The design technique is considered complete, since its model takes into account all DA design parameters; simple, since the designer does not have to deal with the tiny effects (parasitic) that affect DA behavior; versatile, since it does not impose restrictions on the component topologies the designer might be interested to used; and finally, reliable, a crucial criterion for mm-wave design, since model does not apply simplification or neglect parasitic effects. Our end-goal is to offer the designer a different and interesting technique in which the outcome of the suggested CAutoD process is a set of 3D graphical design exploration (DSE) plots. Designers then can explore different possible solutions and choose the best design that meet their multiple performance objectives. Its benefit is demonstrated by exploring the design space of DAs with BWs â„ 80 GHz where STMicroelectronics (ST) 55-nm CMOS process, accessible through the framework of European TARANTO project, is used, reporting 216 feasible DA options to explore from. Two global optimum DAs amplifying frequencies up to 100 GHz were then implemented as circuit prototypes. A single stage DA showing with 6.01 GHz/mW of gain-bandwidth product over DC consumption (GBPâPDC ) is measured and a 17.5 THz GBP cascaded DA with 71.96 GHz/mW of GBPâPDC is proposed, being the highest figure of merits, to the authorsâ knowledge.Ces cinq derniĂšres annĂ©es, lâintensitĂ© du trafic au sein des centres et des rĂ©seaux de donnĂ©es a Ă©tĂ© multipliĂ©e par plus de six (donnĂ©es CISCO) et la tendance va en sâaccentuant. Cette demande pour une plus grande capacitĂ© de stockage et de traitement va de pair avec une qualitĂ© accrue du service aux utilisateurs, entrainant une saturation des bandes de frĂ©quences allouĂ©es aux tĂ©lĂ©communications civiles malgrĂ© les efforts dĂ©ployĂ©s pour amĂ©liorer lâefficacitĂ© spectrale. Dâautres solutions sont Ă©galement Ă©tudiĂ©es pour transmettre des signaux ultra large bande, dont lâexploitation des bandes millimĂ©triques encore peu encombrĂ©es. Dans ce contexte des transmissions radiofrĂ©quences et microondes, lâamplification du signal est une fonction basique qui prĂ©vaut sur lâensemble de la chaĂźne : entrĂ©e, sortie, rĂ©amplification en cours de propagation. Aussi, cette thĂšse sâintĂ©resse-tâelle Ă lâamplification trĂšs large bande dans le domaine du millimĂ©trique, lâamplificateur distribuĂ© sâavĂ©rant ĂȘtre le plus adĂ©quat et le plus performant parmi tous les candidats potentiels. Toutefois, sa conception nâest pas aisĂ©e. En effet, concevoir un circuit intĂ©grĂ© est une gageure en millimĂ©trique du fait des nombreux Ă©lĂ©ments parasites inhĂ©rents aux nĆuds technologiques avancĂ©s considĂ©rĂ©s et Ă la montĂ©e en frĂ©quence. Les mĂ©thodes de conception analytiques traditionnelles, performante aux basses frĂ©quences, perdent en robustesse au-delĂ de 30 GHz. Nous proposons dans cette Ă©tude une mĂ©thodologie de conception simple et efficace, dite CautoD pour Computer Automated Design, basĂ©e sur lâĂ©laboration dâun modĂšle physique du circuit et le recours Ă des algorithmes Ă©voluĂ©s adaptĂ©s au domaine radiofrĂ©quences. Notamment, nous proposons de modĂ©liser les relations entrĂ©e-sortie du DA sous la forme dâune matrice chaine de type ABCD quatre ports, ce qui nâa jamais Ă©tĂ© Ă©tudiĂ© jusquâĂ prĂ©sent pour dĂ©crire le comportement de circuits actifs. La mĂ©thode de conception considĂ©rĂ©e est complĂšte car le modĂšle tient compte de tous les paramĂštres actifs, parasites et passifs du DA ; simple car le concepteur nâa plus Ă tergiverser avec les effets secondaires qui impactent le comportement du circuit ; versatile car la mĂ©thode nâimpose aucune condition quant au choix de topologie ou de technologie du DA ; robuste malgrĂ© les frĂ©quences millimĂ©triques car lâensemble des effets parasites a Ă©tĂ© considĂ©rĂ© pour chacun des blocs Ă©lĂ©mentaires descriptifs du DA. Notre objectif, contrairement aux approches analytiques qui supposent des simplifications excessives, est dâexplorer lâespace de conception sous forme graphique de façon Ă ne conserver que les solutions sâapprochant au mieux du cahier des charges initial. LâintĂ©rĂȘt de notre outil est mis en exergue par lâexploration de lâespace de conception dâamplificateurs distribuĂ©s, de bande passante supĂ©rieure Ă 80 GHz, conçus en technologie STMicroelectronics CMOS 55-nm, accessible dans le cadre du projet europĂ©en TARANTO. Parmi les 216 options disponibles deux ont Ă©tĂ© implĂ©mentĂ©es permettant dâamplifier les frĂ©quences jusquâĂ une centaine de gigahertz. Un DA simple Ă©tage avec 6,01 GHz/mW de produit gain-bande (GBP) rapportĂ© par milliwatt de puissance consommĂ© (GBP/Pdc) a Ă©tĂ© mesurĂ© et un DA cascadĂ© de 17,5 THz de GBP est proposĂ© avec 71.96 GHz/mW of GBP/Pdc. DâaprĂšs nos sources, ce sont les plus forts facteurs de mĂ©rite reportĂ©s jusquâĂ prĂ©sent
Design Tools for Millimeter Wave Ultra Wideband Distributed Amplifiers
Ces cinq derniĂšres annĂ©es, lâintensitĂ© du trafic au sein des centres et des rĂ©seaux de donnĂ©es a Ă©tĂ© multipliĂ©e par plus de six (donnĂ©es CISCO) et la tendance va en sâaccentuant. Cette demande pour une plus grande capacitĂ© de stockage et de traitement va de pair avec une qualitĂ© accrue du service aux utilisateurs, entrainant une saturation des bandes de frĂ©quences allouĂ©es aux tĂ©lĂ©communications civiles malgrĂ© les efforts dĂ©ployĂ©s pour amĂ©liorer lâefficacitĂ© spectrale. Dâautres solutions sont Ă©galement Ă©tudiĂ©es pour transmettre des signaux ultra large bande, dont lâexploitation des bandes millimĂ©triques encore peu encombrĂ©es. Dans ce contexte des transmissions radiofrĂ©quences et microondes, lâamplification du signal est une fonction basique qui prĂ©vaut sur lâensemble de la chaĂźne : entrĂ©e, sortie, rĂ©amplification en cours de propagation. Aussi, cette thĂšse sâintĂ©resse-tâelle Ă lâamplification trĂšs large bande dans le domaine du millimĂ©trique, lâamplificateur distribuĂ© sâavĂ©rant ĂȘtre le plus adĂ©quat et le plus performant parmi tous les candidats potentiels. Toutefois, sa conception nâest pas aisĂ©e. En effet, concevoir un circuit intĂ©grĂ© est une gageure en millimĂ©trique du fait des nombreux Ă©lĂ©ments parasites inhĂ©rents aux nĆuds technologiques avancĂ©s considĂ©rĂ©s et Ă la montĂ©e en frĂ©quence. Les mĂ©thodes de conception analytiques traditionnelles, performante aux basses frĂ©quences, perdent en robustesse au-delĂ de 30 GHz. Nous proposons dans cette Ă©tude une mĂ©thodologie de conception simple et efficace, dite CautoD pour Computer Automated Design, basĂ©e sur lâĂ©laboration dâun modĂšle physique du circuit et le recours Ă des algorithmes Ă©voluĂ©s adaptĂ©s au domaine radiofrĂ©quences. Notamment, nous proposons de modĂ©liser les relations entrĂ©e-sortie du DA sous la forme dâune matrice chaine de type ABCD quatre ports, ce qui nâa jamais Ă©tĂ© Ă©tudiĂ© jusquâĂ prĂ©sent pour dĂ©crire le comportement de circuits actifs. La mĂ©thode de conception considĂ©rĂ©e est complĂšte car le modĂšle tient compte de tous les paramĂštres actifs, parasites et passifs du DA ; simple car le concepteur nâa plus Ă tergiverser avec les effets secondaires qui impactent le comportement du circuit ; versatile car la mĂ©thode nâimpose aucune condition quant au choix de topologie ou de technologie du DA ; robuste malgrĂ© les frĂ©quences millimĂ©triques car lâensemble des effets parasites a Ă©tĂ© considĂ©rĂ© pour chacun des blocs Ă©lĂ©mentaires descriptifs du DA. Notre objectif, contrairement aux approches analytiques qui supposent des simplifications excessives, est dâexplorer lâespace de conception sous forme graphique de façon Ă ne conserver que les solutions sâapprochant au mieux du cahier des charges initial. LâintĂ©rĂȘt de notre outil est mis en exergue par lâexploration de lâespace de conception dâamplificateurs distribuĂ©s, de bande passante supĂ©rieure Ă 80 GHz, conçus en technologie STMicroelectronics CMOS 55-nm, accessible dans le cadre du projet europĂ©en TARANTO. Parmi les 216 options disponibles deux ont Ă©tĂ© implĂ©mentĂ©es permettant dâamplifier les frĂ©quences jusquâĂ une centaine de gigahertz. Un DA simple Ă©tage avec 6,01 GHz/mW de produit gain-bande (GBP) rapportĂ© par milliwatt de puissance consommĂ© (GBP/Pdc) a Ă©tĂ© mesurĂ© et un DA cascadĂ© de 17,5 THz de GBP est proposĂ© avec 71.96 GHz/mW of GBP/Pdc. DâaprĂšs nos sources, ce sont les plus forts facteurs de mĂ©rite reportĂ©s jusquâĂ prĂ©sent.Over the last few years, both data center and network traffic increased by several folds (more than six-folds, as stated by CISCO Systems, Inc.) and are still experiencing an ongoing growth. This demand for higher capacity while meeting with higher end-to-end quality service projects a continuous need for improvements in spectral efficiency enhancement techniques; however, a given spectrum band has its limit of volume it can support before reaching saturation levels. This pushes research efforts towards finding other solutions and a promising one is by exploiting the uncrowded millimeter-wave (mm-wave) spectrum through arranging more bandwidth. Signal amplification is one of the most basic and prevalent circuit function in modern RF- and microwave- systems. On the topic of wideband operation, distributed amplifier (DA) has proved to be a suitable and promising candidate with its ultra-wideband (UWB) performance. Meanwhile, the design of integrated circuit (IC) in mm-wave spectrum is becoming a challenging process due to the unavoidable parasitic that affect circuit performance and complicate design process. The reliability of the conventional design techniques through deriving mathematical equations, a simple and direct design process commonly used at low frequencies, starts to diminish. Another proposed design technique is by combining advanced-scripting languages with a proper physical model; this will lead to a smart and efficient technique of designing mm-wave IC DAs through a process referred as computer-automated design (CAutoD) process. In this thesis, in particular, we propose a novel ABCD-parameter based chain matrix model, which is more famously used in describing and designing passive circuitry. The design technique is considered complete, since its model takes into account all DA design parameters; simple, since the designer does not have to deal with the tiny effects (parasitic) that affect DA behavior; versatile, since it does not impose restrictions on the component topologies the designer might be interested to used; and finally, reliable, a crucial criterion for mm-wave design, since model does not apply simplification or neglect parasitic effects. Our end-goal is to offer the designer a different and interesting technique in which the outcome of the suggested CAutoD process is a set of 3D graphical design exploration (DSE) plots. Designers then can explore different possible solutions and choose the best design that meet their multiple performance objectives. Its benefit is demonstrated by exploring the design space of DAs with BWs â„ 80 GHz where STMicroelectronics (ST) 55-nm CMOS process, accessible through the framework of European TARANTO project, is used, reporting 216 feasible DA options to explore from. Two global optimum DAs amplifying frequencies up to 100 GHz were then implemented as circuit prototypes. A single stage DA showing with 6.01 GHz/mW of gain-bandwidth product over DC consumption (GBPâPDC ) is measured and a 17.5 THz GBP cascaded DA with 71.96 GHz/mW of GBPâPDC is proposed, being the highest figure of merits, to the authorsâ knowledge
Indirect electrical-control through heating of a GeTe phase change switch and Its application to reflexion type phase shifting
International audienceThis paper presents a switch based on GeTe (Germanium-Telluride) phase-change material (PCM) suitable for millimeter-wave applications. A shunt configuration with indirect excitation through heating is proposed to facilitate the implementation process in integrated circuits and to reduce impact on RF signal. Electromagnetic simulations, from 50 GHz up to 70 GHz, of two parallel switches shunted a CPW transmission line (TL) show an overall ON-state resistance (RON) of 3 Ω with an OFF-state capacitance (COFF) of 7.1 fF. This leads to a high Figure-of-Merit with a cutoff frequency of 7.5 THz. The demonstrated performance is validated through the design of a reflection-type phase shifter (RTPS), where a 3-dB branch-line coupler is loaded with tunable-length lines using those shunt-switches. Simulation results of the RTPS show great precision in terms of phase tunability with an insertion loss (IL) less than 2.7 dB at 60 GHz
Integrated Stacked Parallel Plate Shunt Capacitor for Millimeter-Wave Systems in Low-Cost Highly Integrated CMOS Technologies
International audienceThis letter presents a stacked parallel plate (SPP) shunt capacitor (SC) that benefits from metal stack increment with process nodes advancement. It demonstrated high quality ( Q ) factor and high self-resonance frequency (SRF), promoting the design of analog integrated circuits (ICs) in low-cost highly integrated CMOS technologies at the millimeter-wave (mm-wave) frequency range. As a proof-of-concept, an analytical-equation-based design method is also proposed and three ac-grounded capacitors: 300; 600; and 900-fF, are implemented in STMicroelectronics (STM) 55-nm process. Characterization is performed up to 100 GHz. An effective capacitance density of 0.8 fF/μm2 is obtained. Measurements show Q -values reaching up to 14.7 at 100 GHz and equivalent input series resistances with flat wideband behavior reaching at most an average of 0.55 Ω . SRFs of 140 GHz for the 900-fF SPP-SC up to 368 GHz for the 300-fF SPP-SC are also determined from measurements: the highest SRFs for such large capacitances to the authors’ knowledge.</p
Integrated Stacked Parallel Plate Shunt Capacitor for Millimeter-Wave Systems in Low-Cost Highly Integrated CMOS Technologies
International audienceThis letter presents a stacked parallel plate (SPP) shunt capacitor (SC) that benefits from metal stack increment with process nodes advancement. It demonstrated high quality ( Q ) factor and high self-resonance frequency (SRF), promoting the design of analog integrated circuits (ICs) in low-cost highly integrated CMOS technologies at the millimeter-wave (mm-wave) frequency range. As a proof-of-concept, an analytical-equation-based design method is also proposed and three ac-grounded capacitors: 300; 600; and 900-fF, are implemented in STMicroelectronics (STM) 55-nm process. Characterization is performed up to 100 GHz. An effective capacitance density of 0.8 fF/μm2 is obtained. Measurements show Q -values reaching up to 14.7 at 100 GHz and equivalent input series resistances with flat wideband behavior reaching at most an average of 0.55 Ω . SRFs of 140 GHz for the 900-fF SPP-SC up to 368 GHz for the 300-fF SPP-SC are also determined from measurements: the highest SRFs for such large capacitances to the authors’ knowledge.</p
MĂ©thode de conception dâamplificateurs distribuĂ©s millimĂ©triques basĂ©e sur la matrice chaĂźne (ABCD) 4 ports
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