Low actuation-voltage shift in MEMS switch using ramp dual-pulse

This paper proposes a ramp dual-pulse actuation-voltage waveform that reduces actuation-voltage shift in capacitive microelectromechanical system (MEMS) switches. The proposed waveform as well as two reported waveforms (dual pulse, and novel dual-pulse) are analyzed using equivalent-circuit and equation models. Based on the analysis outcome, the paper provides a clear understanding of trapped charge density in the dielectric. The results show that the proposed actuation-voltage waveform successfully reduces trapped charge and increases lifetime due to lowering of actuation-voltage shift. Using the proposed actuation-voltage waveform, the membrane reaches a steady state on the electrode faster.<br /

Optimal readout schemes in SPAD-based time-correlated event detection sensor for quantum imaging applications

open3MOS SPAD imagers are potentially good candidates for detection of entangled photons in Quantum Imaging applications thanks to their sub-nanosecond time-resolved capabilities and highly parallel readout. In this context, the low number of photons that are typically detected corresponds to a very sparse data matrix. A full readout of raw data is therefore a waste of time and power. We have implemented a sensor architecture to improve the efficiency of the observation up to 8.46% in a TDC-based pixel structure. A tunable current source is used per pixel to establish a global current. This global current presents a real-time status of the whole pixel array in terms of triggered SPADs. The proposed solution requires minimal extra pixel electronics, with little impact on the fill factor and allows an observation rate of up to 8.5 Mfps.Zarghami, Majid; Gasparini, Leonardo; Stoppa, DavidZarghami, Majid; Gasparini, Leonardo; Stoppa, Davi

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

High Dynamic Range Imaging with TDC-Based CMOS SPAD Arrays

This paper investigates the use of image sensors based on complementary metal–oxide–semiconductor (CMOS) single-photon avalanche diodes (SPADs) in high dynamic range (HDR) imaging by combining photon counts and timestamps. The proposed method is validated experimentally with an SPAD detector based on a per-pixel time-to-digital converter (TDC) architecture. The detector, featuring 32 × 32 pixels with 44.64-µm pitch, 19.48% fill factor, and time-resolving capability of ~295-ps, was fabricated in a 150-nm CMOS standard technology. At high photon flux densities, the pixel output is saturated when operating in photon-counting mode, thus limiting the DR of this imager. This limitation can be overcome by exploiting the distribution of photon arrival times in each pixel, which shows an exponential behavior with a decay rate dependent on the photon flux level. By fitting the histogram curve with the exponential decay function, the extracted time constant is used to estimate the photon count. This approach achieves 138.7-dB dynamic range within 30-ms of integration time, and can be further extended by using a timestamping mechanism with a higher resolution

Impact of carbon material on RF MEMS switch

Carbon materials such as Graphene and carbon nano tube promise a new generation of RF NEMS devices that bring many advantages due to their very high performances such as low mass, high Young\u27s modulus and electrical conductivity. In this paper, the properties of Graphene for RF M/NEMS applications are briefly described. We compare the mechanical behaviour of Graphene switches with metallic RF MEMS switches such as Aluminium and Gold. The analytical study and simulation results show that the actuation voltage of Al and Au switches is high (35 V) whereas the actuation voltage for the Graphene switch is low (7.7 V). Also, the switching time of Graphene switch is 3.5 ns while the switching time for metallic switches is approximately 17&mu;s

Design and simulation of a high isolation RF MEMS shunt capacitive switch for C-K band

This paper presents a wide band RF MEMS capacitive switch. The LC resonant frequency is reduced from mm wave to X band frequencies at down-state by using a meander type membrane, with the frequency band is being increased by adding two short high impedance lines at both ends of coplanar waveguide (CPW). Moreover, this acts as T-match circuit in up-state position and improves the matching. Simulation results demonstrate that the capacitance ratio reduces from 50 to 21.4, S21 and S11 are less than &minus;10dB for the entire frequency band at down-state and up-state. Also, a comprehensive and complete electric model of the switch is proposed and simulation results agree well with the characteristics of the physical structure of the MEMS switch. Vpull-in and Vpull-out of this switch are 8.1V and 0.3V, respectively

Network analysis of early maladaptive schemes and career adaptability of students

Background: Numerous studies have shown that early maladaptive schemes play a role in various aspects of human life, but there is a research gap in the relationship between these schemes and career path adaptability. Aims: The aim of this study was to investigate the relationships between early maladaptive schemes and adaptability of students' career path by network analysis. Methods: The research method was descriptive, correlational and research tools were Young's Scheme Questionnaire (1990) and Savickas' Career Adaptability Questionnaire (2012). The statistical population included all students of universities and higher education institutions in the country in 2019, sampling method was non-random with maximum variation and the sample size was 849 people. Questionnaires were provided to students through Google Docs. Network analysis, R software and Qgragh package were used for data analysis. Results: Based on the betweenness index, Unrelenting Standards scheme (20) and the confidence (19) were ranked first. Also, the shortest path between adaptability dimensions and schemes was obtained separately: The dimension of Concern, with the schemes of Approval-Seeking (10/21), Subjugation(10/76) and Insufficient Self- control(13/17), Control dimension, with schemes of Emotional Deprivation(9/99), Insufficient Self-Control(10/69) and Unrelenting Standards(11/76), Curiosity dimension with Insufficient Self-control(10/26), Emotional deprivation(10/99) and Mistrust(11/21), And the dimension of Confidence with Insufficient Self-control(8/10), Unrelenting Standards(9/17) and Failure to Achive(10/36), have the shortest distance, respectively. Conclusion: The results showed that from 18 early maladaptive scheme, 8 schemes of Approval-Seeking, Subjugation, Insufficient self-control, Emotional Deprivation, Unrelenting Standards, Entitlement, Mistrust and Failure to Achive have the most role in various dimensions of students' career path adaptability

Design and simulation of a high isolation RF MEMS shunt capacitive switch for C-K band

Design and simulation of a high isolation RF MEMS shunt capacitive switch for C-K ban