On Chip Counting and Localisation of Magnetite Pollution Nanoparticles

Magnetic nanoparticles are generally smaller than 200 nm surrounding our environment and can easily enter the human brain through the respiratory system. The harm of such nanoparticles may endanger people’s health. This paper focuses on modelling and simulation based on a new kind of magnetic sensors, which can count and localize these magnetite nanoparticles. The proposed sensors could help to prevent these nanoparticles from the polluted environment and undoubtedly reduce their adverse risks to humans. The modelled magnetic system consists of a tunnelling magnetoresistive (TMR) sensor array, a conducting line, and the detected magnetite nanoparticles. The localization and quantization of these nanoparticles can be achieved by analysing total output voltages from the TMR sensor array

Sub-Femto-Farad Resolution Electronic Interfaces for Integrated Capacitive Sensors: A Review

Capacitance detection is a universal transduction mechanism used in a wide variety of sensors and applications. It requires an electronic front-end converting the capacitance variation into another more convenient physical variable, ultimately determining the performance of the whole sensor. In this paper we present a comprehensive review of the different signal conditioning front-end topologies targeted in particular at sub-femtofarad resolution. Main design equations and analysis of the limits due to noise are reported in order to provide the designer with guidelines for choosing the most suitable topology according to the main design specifications, namely energy consumption, area occupation, measuring time and resolution. A data-driven comparison of the different solutions in literature is also carried out revealing that resolution, measuring time, area occupation and energy/conversion lower than 100 aF, 1 ms 0.1 mm2, and 100 pJ/conv. can be obtained by capacitance to digital topologies, which therefore allow to get the best compromise among all design specifications

Energy-efficient memcapacitor devices for neuromorphic computing

Data-intensive computing operations, such as training neural networks, are essential for applications in artificial intelligence but are energy intensive. One solution is to develop specialized hardware onto which neural networks can be directly mapped, and arrays of memristive devices can, for example, be trained to enable parallel multiply–accumulate operations. Here we show that memcapacitive devices that exploit the principle of charge shielding can offer a highly energy-efficient approach for implementing parallel multiply–accumulate operations. We fabricate a crossbar array of 156 microscale memcapacitor devices and use it to train a neural network that could distinguish the letters ‘M’, ‘P’ and ‘I’. Modelling these arrays suggests that this approach could offer an energy efficiency of 29,600 tera-operations per second per watt, while ensuring high precision (6–8 bits). Simulations also show that the devices could potentially be scaled down to a lateral size of around 45 nm

A CMOS hall sensor modelling with readout circuitry and microcontroller processing for magnetic detection

A Hall sensor array system for magnetic field detection and analysis is realized in X-FAB 0.18 μm CMOS technology. Magnetic field detection is attributed to the magnetization of metal coils to metal particles and the sensing characteristics of the Hall sensor array. The system puts forward a complete solution from Hall sensors, analog front-end circuit, analog-to-digital converter (ADC) to microcontroller unit. Using Ansoft Maxwell and COMSOL Multiphysics software for simulation verification, the minimum diameter of magnetic particles that can be detected in the system is 2 μm. The measured signal to noise and distortion ratio, spurious free dynamic range, and effective number of bits of the proposed ADC are 70.61 dB, 90.08 dB, and 11.44-bit, respectively. The microsystem based on STM32 combines hardware and software design, which can effectively adjust the motion parameters and realize the real-time display in the LCD screen of the magnetic field and voltage information. Compared to the prior system, the portability, cost, and efficiency have been considerably improved, which is aimed at the rapid measurement of heavy metal particles such as Fe, Co, and Ni in ambient air and blood

High-precision fluorescence photometry for real-time biomarkers detection

Les derniers évènements planétaires et plus particulièrement l'avènement sans précédent du nouveau coronavirus augmente la demande pour des appareils de test à proximité du patient. Ceux-ci fonctionnent avec une batterie et peuvent identifier rapidement des biomarqueurs cibles. Pareils systèmes permettent aux utilisateurs, disposant de connaissances limitées en la matière, de réagir rapidement, par exemple dans la détection d'un cas positif de COVID-19. La mise en œuvre de l'élaboration d'un tel instrument est un projet multidisciplinaire impliquant notamment la conception de circuits intégrés, la programmation, la conception optique et la biologie, demandant tous une maîtrise pointue des détails. De plus, l'établissement des spécifications et des exigences pour mesurer avec précision les interactions lumière-échantillon s'additionnent au besoin d'expérience dans la conception et la fabrication de tels systèmes microélectriques personnalisés et nécessitent en elles-mêmes, une connaissance approfondie de la physique et des mathématiques. Ce projet vise donc à concevoir et à mettre en œuvre un appareil sans fil pour détecter rapidement des biomarqueurs impliqués dans des maladies infectieuses telles que le COVID-19 ou des types de cancers en milieu ambulatoire. Cette détection se fait grâce à des méthodes basées sur la fluorescence. La spectrophotométrie de fluorescence permet aux médecins d'identifier la présence de matériel génétique viral ou bactérien tel que l'ADN ou l'ARN et de les caractériser. Les appareils de paillasse sont énormes et gourmand énergétiquement tandis que les spectrophotomètres à fluorescence miniatuarisés disponibles dans le commerce sont confrontés à de nombreux défis. Ces appareils miniaturisés ont été découverts en tirant parti des diodes électroluminescentes (DEL) à semi-conducteurs peu coûteuses et de la technologie des circuits intégrés. Ces avantages aident les scientifiques à réduire les erreurs possibles, la consommation d'énergie et le coût du produit final utilisé par la population. Cependant, comme leurs homologues de paillasse, ces appareils POC doivent quantifier les concentrations en micro-volume d'analytes sur une large gamme de longueurs d'onde suivant le cadre d'une économie en ressources. Le microsystème envisagé bénéficie d'une approche de haute précision pour fabriquer une puce microélectronique CMOS. Ce procédé se fait de concert avec un boîtier personnalisé imprimé en 3D pour réaliser le spectrophotomètre à la fluorescence nécessaire à la détection quantitative d'analytes en microvolume. En ce qui a trait à la conception de circuits, une nouvelle technique de mise à auto-zeroing est appliquée à l'amplificateur central, celui-ci étant linéarisé avec des techniques de recyclage et de polarisation adaptative. Cet amplificateur central est entièrement différentiel et est utilisé dans un amplificateur à verrouillage pour récupérer le signal d'intérêt éclipsé par le bruit. De plus, l'augmentation de la sensibilité de l'appareil permet des mesures quantitatives avec des concentrations en micro-volume d'analytes ayant moins d'erreurs de prédiction de concentration. Cet avantage cumulé à une faible consommation d'énergie, un faible coût, de petites dimensions et un poids léger font de notre appareil une solution POC prometteuse dans le domaine de la spectrophotométrie de fluorescence. La validation de ce projet s'est fait en concevant, fabriquant et testant un prototype discret et sans fil. Son article de référence a été publié dans IEEE LSC 2018. Quant à la caractérisation et l'interprétation du prototype d'expériences in vitro à l'aide d'une interface MATLAB personnalisée, cet article a été publié dans IEEE Sensors journal (2021). Les circuits intégrés et les photodétecteurs ont été fabriqués ont été conçus et fabriqués par Cadence en 2019. Relativement aux solutions de circuit proposées, elles ont été fabriquées avec la technologie CMOS 180 nm et publiées lors de la conférence IEEE MWSCAS 2020. Tout comme cette dernière contribution, les expériences in vitro avec le dispositif proposé incluant la puce personnalisée et le boîtier imprimé en 3D ont été réalisés et les résultats électriques et optiques ont été soumis au IEEE Journal of Solid-State Circuits (JSSC 2022).The most recent and unprecedented experience of the novel coronavirus increases the demand for battery-operated near-patient testing devices that can rapidly identify the target biomarkers. Such systems enable end-users with limited resources to quickly get feedback on various medical tests, such as detecting positive COVID-19 cases. Implementing such a device is a multidisciplinary project dealing with multiple areas of expertise, including integrated circuit design, programming, optical design, and biology, each of which needs a firm grasp of details. Alongside the need for experience in designing and manufacturing custom microelectronic systems, establishing the specifications and requirements to precisely measure the light-sample interactions requires an in-depth knowledge of physics and mathematics. This project aims to design and implement a wireless point-of-care (POC) device to rapidly detect biomarkers involved in infectious diseases such as COVID-19 or different types of cancers in an ambulatory setting using fluorescence-based methods. Fluorescence spectrophotometry allows physicians to identify and characterize viral or bacterial genetic materials such as DNAs or RNAs. The benchtop devices that are currently available are bulky and power-hungry, whereas the commercially available miniaturized fluorescence spectrophotometers are facing many challenges. Many of these difficulties have been resolved in literature thanks to inexpensive semiconductor light-emitting diodes (LEDs) and integrated circuits technology. Such advantages aid scientists in decreasing the size, power consumption, and cost of the final product for end-users. However, like the benchtop counterparts, such POC devices must quantify micro-volume concentrations of analytes across a wide wave length range under an economy of resources. The envisioned microsystem benefits from a high-precision approach to fabricating a CMOS microelectronic chip combined with a custom 3D-printed housing. This implementation results in a fluorescence spectrophotometer for qualitative and quantitative detection of micro-volume analytes. In terms of circuit design, a novel switched-biasing ping-pong auto-zeroed technique is applied to the core amplifier, linearized with recycling and adaptive biasing techniques. The fully differential core amplifier is utilized within a lock-in amplifier to retrieve the signal of interest overshadowed by noise. Increasing the device's sensitivity allows quantitative measurements down to micro-volume concentrations of analytes with less concentration prediction error. Such an advantage, along with low-power consumption, low cost, low weight, and small dimensions, make our device a promising POC solution in the fluorescence spectrophotometry area. The approach of this project was validated by designing, fabricating, and testing a discrete and wireless prototype. Its conference paper was published in IEEE LSC 2018, and the prototype characterization and interpretation of in vitro experiments using a custom MATLAB interface were published in IEEE Sensors Journal (2021). The integrated circuits and photodetectors were designed and fabricated by the Cadence circuit design toolbox (2019). The proposed circuit solutions were fabricated with 180-nm CMOS technology and published at IEEE MWSCAS 2020 conference. As the last contribution, the in vitro experiments with the proposed device, including the custom chip and 3D-printed housing, were performed, and the electrical and optical results were submitted to the IEEE Journal of Solid-State Circuits (JSSC 2022)

Multichannel 65 zF rms Resolution CMOS Monolithic Capacitive Sensor for Counting Single Micrometer-Sized Airborne Particles on Chip

The first integrated CMOS monolithic sensor system for on-chip capacitive detection of micrometric airborne particulate matter (PM) is presented. The chip is based on a 32 channel lock-in architecture allowing a dust collection area of 1.15 mm2 where interdigitated differential microelectrodes, fabricated with the top metal and directly exposed to air, allow single particle sensitivity. The preamplifier input capacitance is significantly minimized thanks to the electrode-amplifier proximity and proper partitioning of the sensing area, in order to reduce the noise. Each channel comprises a charge preamplifier with adjustable high-pass filtering for flicker noise shaping, square-wave mixer, gm-C tunable low-pass filter (40-750 Hz), and a 6 bit digital network for automatic compensation of electrodes mismatching with a granularity of 150 aF. Thanks to the capacitive noise of only 65 zF rms with 25 ms temporal resolution, deposition events of single mineral talc particles were recorded down to 1μm diameter with a signal-to-noise ratio of 18dB. This chip paves the way to pervasive mapping of both indoor and outdoor PM in the 1-30 μm range

NASA Tech Briefs, December 1997

Topics: Design and Analysis Software; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Software; Mechanics; Manufacturing/Fabrication; Mathematics and Information Sciences; Books and Reports

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion