Papers by Andrea De Marcellis
Laser Transmission Spectroscopy Based on Tunable-Gain Dual-Channel Dual-Phase LIA for Biological Nanoparticles Characterization
IEEE Transactions on Biomedical Circuits and Systems
High-Sensitivity Differential Interface for the Detection of Energy Variations of Nanosecond Laser Pulses for Spectroscopic Applications
IEEE Sensors Journal
A True Random Number Generator Architecture Based on a Reduced Number of FPGA Primitives
AEU - International Journal of Electronics and Communications
Abstract This paper reports on the design, realization and characterization of a True Random Numb... more Abstract This paper reports on the design, realization and characterization of a True Random Number Generator (TRNG) that operates using as seeds of entropy, the jitter and the metastability introduced by primitives of a Field Programmable Gate Arrays (FPGA) board. In particular, the TRNG architecture has been implemented on a Xilinx Ultrascale XCKU040 FPGA board. Generally, the implementations on FPGA of fully-digital TRNGs make use of ring oscillators employing a large number of Look-Up-Table (LUT) blocks. Differently from this approach, this paper demonstrates that a reliable FPGA-based TRNG architecture can be realized mainly employing only a single PLL and three on-board primitives together with other few basic logic elements (i.e., 8 D-type Flip-Flop, 17 LUT and 2 Counters) used only for the initial overall system synchronization and post-processing operations. In this way, the proposed solution largely reduces the employed number of the FPGA Configurable Logic Blocks (CLB), the circuitry complexity and the overall power consumption without affecting the achievable output bit rate so resulting suitable for full-custom VLSI implementations. The random and statistical properties of the generated 100 Mbps output bitstreams have been validated by passing all the National Institute of Standards and Technology (NIST) tests as well as the Anderson-Darling and the Kolmogorov-Smirnov tests so demonstrating that the proposed TRNG architecture can be suitably employed in security/cybersecurity network systems as well as, once integrated, in Internet-of-Things (IoT) and Industrial-Internet-of-Things (IIoT) applications.
Metasurface based on Cross-Shaped Plasmonic Nanoantennas as Chemical Sensor for Surface-Enhanced InfraRed Absorption Spectroscopy
Sensors and Actuators B: Chemical
Abstract Infrared spectroscopy is an effective technique extensively used in research and industr... more Abstract Infrared spectroscopy is an effective technique extensively used in research and industry for the label-free and unambiguous identification of molecular species. However, the sensitivity of this technique is severely limited as a result of Beer’s law and, the small infrared absorption cross-section that make prohibitively weak the absorption signals, of minute amounts of analyte as those present in monolayers. This limitation can be overcome by enhancing the infrared vibration of molecules through the enhancement of the electromagnetic (EM) field. Surface Enhanced InfraRed Absorption (SEIRA) using resonant metal Nano-scale Antennas (NAs) can provide huge electromagnetic fields on the nanometer scale featuring localized collective oscillations of electrons, an effect named Localized Surface Plasmonic Resonances (LSPRsWe here report on a series of 2D arrays of cross-shaped NAs having several mm2 area coverage (metasurface) as SEIRA optimized antennas, which can be used in practical applications such as the vibrational sensing of chemical and biological analytes. Cross-shape designed NAs are insensitive to the polarization of the electromagnetic radiation impinging the active area. Due to the random orientation of the dipole moments of molecules they are particularly suitable for the construction of bio-molecular sensors. At the same time, the 2D-array configuration ensures a good near-field signal enhancement arising from the coupling between neighbour NAs Moreover, SEIRA NAs can be easily integrated with micrometre-sized channels and be suitable for the high sensitivity, real time analysis of IR emitting samples, in matrices where IR spectroscopy is severely limited due to absorption bands of liquid water. We present the design, fabrication and experimental characterization of large-area metasurfaces based on cross-shaped plasmonic NAs for the spectroscopic characterization of various types of compounds and for sensing applications in the mid-infrared range. The cross-shaped NAs we have designed exhibit SEIRA phenomena which are very sensitive to both refractive index changes in the surrounding medium and to the specific molecular vibration band emerging from surface adsorbed molecules. To test this effect on our device, we have used as model compounds small molecules (molecular weight (MW)
Proceedings
A Current-Mode (CM) TransImpedance Amplifier (TIA) based on Second Generation Current Conveyors (... more A Current-Mode (CM) TransImpedance Amplifier (TIA) based on Second Generation Current Conveyors (CCIIs) for capacitive microsensor measurements is presented. The designed electronic interface performs a capacitance-to-voltage conversion using 3 CCIIs and 3 resistors exploiting a synchronous-demodulation technique to improve the overall detection sensitivity and resolution of the system. A CM-TIA solution designed at transistor level in AMS0.35 µm integrated CMOS technology with a power consumption lower than 900 µW is proposed. Experimental results obtained with a board-level prototype show linear behavior of the proposed interface circuit with a resolution up to 34.5 fF and a sensitivity up to 223 mV/nF, confirming the theoretical expectations.
Sensors and Actuators B: Chemical
ZnS-Ag 2 S core-shell nano/hetero-junctions have been synthesized by a two-step co-precipitation ... more ZnS-Ag 2 S core-shell nano/hetero-junctions have been synthesized by a two-step co-precipitation technique, in which thin layers of Ag 2 S have been successfully coated on the surface of ZnS nanospheres. Structural studies and elemental analysis have been performed using X-ray diffraction, Fourier transfer infrared spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, and high-resolution transmission electron microscopy. UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy have been employed to investigate linear optical characteristics. Nanosecond laser pulsed-based single-beam Z-scan analysis has been used to examine the magnitude and the sign of the third-order nonlinear refractive indices. Samples show negative values of nonlinear refractive indices indicating self-defocusing optical nonlinearity under 1064 nm excitation. The results have shown that the third-order nonlinear refractive index in ZnS nanospheres can reach the magnitude of 61.0 × 10 −12 m 2 ∕W by encapsulating such a nanostructure within nanometer shells of Ag 2 S. The enhanced nonlinearity for ZnS-Ag 2 S core-shells has been found to be 9 times higher than sole ZnS nanoparticles, which was estimated to be about 6.4 × 10 −12 m 2 ∕W.
CCII-Based Voltage Amplifier Optimization for Reduced Relative Gain Error
Circuits, Systems, and Signal Processing
Proceedings
In this paper we report on the results of the simulations of the electromagnetic properties of a ... more In this paper we report on the results of the simulations of the electromagnetic properties of a metasurface composed of a 2D-array of plasmonic nanoantennas acting as polarisation insensitive dual band THz perfect absorber able to achieve absorption coefficients and quality factors up to 99.6% and 122, respectively. The 2D-array is designed on top of a polyimide flexible film separating it from an Ag ground layer. The plasmonic nanoantenna is composed of two Ag quadrangular rings and an Ag diamond-shape dot is placed at their geometrical centre. The absorption resonances show a linear frequency shift with respect to variations of the refractive index of transparent substances adsorbed on the metasurface. This allows the dual-band absorber to be employed as a sensor of the chemical/physical modifications taking place on the substance. In particular, in terms of the refractive index units, the sensor based on the dual-band absorber can achieve sensitivities up to 310 GHz/RIU.
A CCII-based non-inverting Schmitt trigger and its application as astable multivibrator for capacitive sensor interfacing
International Journal of Circuit Theory and Applications, 2016
One-Decade Frequency Range, In-Phase Auto-Aligned 1.8 V 2 mW Fully Analog CMOS Integrated Lock-In Amplifier for Small/Noisy Signal Detection
IEEE Sensors Journal, 2016
Sensors, 2016
Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors ... more Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors are the preferred choice in many applications demanding the measurement of low magnetic fields in small volumes. This rapid deployment from theoretical basis to market and state-of-the-art applications can be explained by the combination of excellent inherent properties with the feasibility of fabrication, allowing the real integration with many other standard technologies. In this paper, we present a review focusing on how this capability of integration has allowed the improvement of the inherent capabilities and, therefore, the range of application of GMR sensors. After briefly describing the phenomenological basis, we deal on the benefits of low temperature deposition techniques regarding the integration of GMR sensors with flexible (plastic) substrates and pre-processed CMOS chips. In this way, the limit of detection can be improved by means of bettering the sensitivity or reducing the noise. We also report on novel fields of application of GMR sensors by the recapitulation of a number of cases of success of their integration with different heterogeneous complementary elements. We finally describe three fully functional systems, two of them in the biotechnology world, as the proof of how the integrability has been instrumental in the meteoric development of GMR sensors and their applications.
A Novel Calibration-Less CCII-Based Resistance-to-Time Front-End for Gas Sensor Interfacing
We present a novel currentmode fullyintegrable oscillating circuit for the interfacing of resis... more We present a novel currentmode fullyintegrable oscillating circuit for the interfacing of resistive gas sensors, using a reduced number of active blocks, in particular low voltage low power Second Generation Current Conveyors (CCIIs), to be used in portable applications. ...
A novel uncalibrated OA-based sensor interface for capacitive/resistive sensor applications
IET Circuits, Devices and Systems
Iet Circuits Devices & Systems, 2014
In this study, the authors report on two different electronic interfaces for low-power integrated... more In this study, the authors report on two different electronic interfaces for low-power integrated circuits electric current monitoring through current-to-frequency (I-f) conversion schemes. This proposal displays the intrinsic advantages of the quasidigital systems regarding direct interfacing and self-calibrating capabilities. In addition, as current-sensing devices, they have made use of the giant magnetoresistance (GMR) technology because of its high sensitivity and compatibility with standard complementary metal oxide semiconductor processes. Single elements and Wheatstone bridges based on spin-valves and magnetic tunnel junctions have been considered. In this sense, schematic-level simulations for integration in Austria Microsystems 0.35 μm technology have been corroborated by means of experimental measurements with the help of printed circuit board prototypes and real GMR devices. Tables with relevant parameters (silicon area, power consumption, sensitivity etc.) have been constructed as practical tools for designers. Electric currents down to 2 μA have been resolved in this way.
We report on the development of a novel modulation technique for UWB wireless optical
communicati... more We report on the development of a novel modulation technique for UWB wireless optical
communication systems for application in a transcutaneous biotelemetry. The solution, based on the
generation of short laser pulses, allows for a high data rate link whilst achieving a significant power
reduction (energy per bit) compared to the state-of-the-art. These features make this particularly
suitable for emerging biomedical applications such as implantable neural/biosensor systems. The
relatively simple architecture consists of a transmitter and receiver that can be integrated in a standard
CMOS technology in a compact Silicon footprint. These parts include circuits for bias and drive
current generation, conditioning and processing, optimised for low-voltage/low-power operation.
Preliminary experimental findings validate the new paradigm and show good agreement with expected
results. The complete system achieves a BER less than 10^-7, with maximum data rate of 125Mbps and
estimated total power consumption of less than 3mW.
Procedia Engineering, 2015
Aim of this paper is to compare the electrical responses to sub-ppm NO 2 gas concentrations of WO... more Aim of this paper is to compare the electrical responses to sub-ppm NO 2 gas concentrations of WO 3 electrospun nanofibers both activated by thermal (in the temperature range 25°C -150°C) and/or light-radiating conditions (Red λ=670nm, Green λ=550nm, and Purple Blue λ=430nm). Blue light resulted the most effective light source with respect to the others. Light illumination at room temperature improves the base line recovery and response time, whereas temperature enhances relative response, with a maximum at 75°C. Light-radiating room temperature gas detection yields a satisfactory response despite the reduction of sensor gas sensitivity. Light induced electrical response mechanisms are presented and discussed.
Procedia Engineering, 2015
In this work we demonstrate that the phase shift detection technique can be applied to reveal, wi... more In this work we demonstrate that the phase shift detection technique can be applied to reveal, with very high sensitivity and resolution, concentrations of chemical/biological substances optically detectable by measuring power variations of a light source. The system is based on the synchronous demodulation technique and employs a Si photodiode (PD) operating in photovoltaic regime biased through a small modulating sinusoidal waveform. The phase shift variations are measured between this biasing voltage and that one generated by the Si PD illuminated by the light, that interacts with the chemical/biological sample under analysis, providing the phase shift change. Experimental results demonstrate that is possible to achieve phase detection sensitivity, with respect to light power variations, up to 3100°/μW as a function of the Si PD settable operating conditions. By using a commercial lock-in amplifier with a 0.01° phase resolution, a light power variation resolution of about 3pW has been achieved. As a case-example, variations of the molar concentration of a methylene blue solution are detected by performing optical absorption standard measurements. Despite the phase resolution limitation of the used lock-in amplifier, the comparison between the data obtained through the proposed technique and those ones achieved by conventional amplitude measurements demonstrates a high improvement of the detection sensitivity. As a consequence, the measurement of molar concentration variations with a resolution of 80pM is achieved resulting 33 times higher than that one obtained with the amplitude detection.
Procedia Engineering, 2015
In this paper we report on the optimisation of the optical characteristics of 2D-arrays of plasmo... more In this paper we report on the optimisation of the optical characteristics of 2D-arrays of plasmonic gold nanoantennas (NA) that can be used as high sensitivity mid-infrared spectroscopic sensor for the detection of chemical/biological substances by using the Surface Enhanced Infrared Absorption (SEIRA) technique. This approach allows to detect the presence of a substance adsorbed on the NA by measuring its optical absorption under the conditions for which the maximum of the reflectivity response of the 2D-array occurs at the same wavelength of the substance maximum absorption peak. In particular, by acting on the 2D-array periodicity, NA shape, size and thickness, numerical simulations of the 2D-array detection response, based on Finite Element Method (FEM), demonstrate that is possible to obtain an increase in the detection sensitivity of more than three orders of magnitude with respect to that one achievable if the same substance is deposited on an unstructured planar metal surface, independently from the wavelength at which the substance absorption occurs. Moreover, we present the results of an analysis of the dependence of the 2D-array maximum reflectivity and peak wavelength on the geometrical parameters characterising the NA and the 2D-array.
The Current-Mode Approach in Sensor Interfaces Design
Analog Circuits and Systems for Voltage-Mode and Current-Mode Sensor Interfacing Applications, 2011
In this chapter, considering the Second Generation Current Conveyor (CCII) as the main active blo... more In this chapter, considering the Second Generation Current Conveyor (CCII) as the main active block in Current-Mode (CM) approach, as an alternative to OA utilized in VM design, some CM interface solutions both for resistive and capacitive sensors will be described at system level. The presented circuits have been implemented as discrete element prototype PCBs, using commercial components and, sometimes,
Uncalibrated operational amplifier-based sensor interface for capacitive/resistive sensor applications
IET Circuits, Devices & Systems, 2015
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Papers by Andrea De Marcellis
communication systems for application in a transcutaneous biotelemetry. The solution, based on the
generation of short laser pulses, allows for a high data rate link whilst achieving a significant power
reduction (energy per bit) compared to the state-of-the-art. These features make this particularly
suitable for emerging biomedical applications such as implantable neural/biosensor systems. The
relatively simple architecture consists of a transmitter and receiver that can be integrated in a standard
CMOS technology in a compact Silicon footprint. These parts include circuits for bias and drive
current generation, conditioning and processing, optimised for low-voltage/low-power operation.
Preliminary experimental findings validate the new paradigm and show good agreement with expected
results. The complete system achieves a BER less than 10^-7, with maximum data rate of 125Mbps and
estimated total power consumption of less than 3mW.