Càndid Reig - Universitat de València (original) (raw)

Papers by Càndid Reig

Electronics

Flash converters are suitable analog-to-digital converter architectures for high-speed applicatio... more Flash converters are suitable analog-to-digital converter architectures for high-speed applications. However, the benefits in terms of the frequency of smaller technology nodes are hampered by variability, which necessitates the use of large transistors. Comparator redundancy was introduced to overcome this trade-off; the best comparators were selected upfront (either at start-up or in the factory), and the unused comparators could be switched off. This work studies the possibility of performing comparator selection in the background concurrently with normal conversion to increase the converter lifetime. Thus, the system can automatically recover its performance from drifts or failures due to aging, temperature, etc. This paper proposes an embedded solution that includes a calibration stimulus generator (which only requires some external passive elements) and develops system design requirements. In addition, mathematical equations and error sensitivities of the system elements were ...

a series of events initiated in 2008, capturing the advances on special circuits, electronics, an... more a series of events initiated in 2008, capturing the advances on special circuits, electronics, and microelectronics on both theory and practice, from fabrication to applications using these special circuits and systems. The topics cover fundamentals of design and implementation, techniques for deployment in various applications, and advances in signal processing. Innovations in special circuits, electronics and microelectronics are the key support for a large spectrum of applications. The conference is focusing on several complementary aspects and targets the advances in each on it: signal processing and electronics for high speed processing, micro-and nano-electronics, special electronics for implantable and wearable devices, sensor related electronics focusing on low energy consumption, and special applications domains of telemedicine and ehealth, bio-systems, navigation systems, automotive systems, home-oriented electronics, bio-systems, etc. These applications led to special des...

2017 Spanish Conference on Electron Devices (CDE), Feb 1, 2017

Nanostructured ZnO layers have been deposited onto SiO 2 /Si substrates by spray pyrolysis, with ... more Nanostructured ZnO layers have been deposited onto SiO 2 /Si substrates by spray pyrolysis, with previously patterned interdigitated gold electrodes. We have then measured the capacitive and resistive response against ambient parameters such as relative humidity and illumination.

Advanced Giant Magnetoresistance (GMR) sensors for Selective-Change Driven (SCD) circuits

2021 13th Spanish Conference on Electron Devices (CDE), 2021

Nowadays, bio-inspiration is driving novel sensors designs, beyond vision sensors. By taking adva... more Nowadays, bio-inspiration is driving novel sensors designs, beyond vision sensors. By taking advantage of their compatibility with standard CMOS technologies, the integration of giant magneto-resistance (GMR) based magnetic sensors within such event-driven approaches is proposed. With this aim, several topologies of such GMR sensors have been designed, fabricated and characterized. In addition, integrated circuit interfaces of a standard CMOS technology are also proposed. Their suitability for this approach is then demonstrated by means of Cadence IC simulations.

Creixement cristaltextperiodcentered l'i i caracterització fonamental de semiconductors semimagnvctics de gap estret

Microwave and Optical Technology Letters, 2008

A low cost directive uniplanar broadband printed Quasi-Yagi antenna design is presented. As a par... more A low cost directive uniplanar broadband printed Quasi-Yagi antenna design is presented. As a particular realization, some prototypes have been designed to operate in the 2.45 GHz band. They have been then modeled, fabricated onto standard printed circuit dielectric substrate and tested successfully. For the design and the modeling processes, we have make use of FDTD based in-house developed algorithms. The obtained bandwidth is, for all the considered cases, better than 15%. The main radiation characteristics are 2-5.5 dBi gain, depending on the number of director elements, and better than 25 dB front-to-back ratio. Overall antenna size was, in any case lesser than 1 ϫ 0.5 .

Microwave and Optical Technology Letters, 1996

I c I \ g=0.5 g=0.3

Journal of Crystal Growth, 1999

To reduce Hg high pressure related to the high-temperature synthesis reaction between the compone... more To reduce Hg high pressure related to the high-temperature synthesis reaction between the components in elemental form, Hg \V Mn V Te bulk crystals were produced by a two-step procedure including (I) the alloy synthesis using HgTe crystals grown by the cold travelling heater method and elemental Mn and Te to complete the desired composition, followed by (II) the Bridgman growth. The growth was carried out at temperature in the range of 700-850°C and rate of 1 mm/h. The Hg \V Mn V Te crystals have been characterised by X-ray diffractometry, energy dispersive X-ray analysis, Fourier transformed infrared spectroscopy and Hall effect techniques. Although the distribution coefficient of Mn was found to be in the range of 3-3.5 in the first-to-freeze region, the crystals show a good axial composition uniformity throughout more than a half of the total length. The lattice parameter of Hg \V Mn V Te is reported for the studied composition range x"0-0.15.

Growth and characterization of GdxHg1−xSe crystals

Journal of Crystal Growth, 2008

The growth of GdxHg1−xSe crystals by the vertical Bridgman method was studied in the composition ... more The growth of GdxHg1−xSe crystals by the vertical Bridgman method was studied in the composition range 0⩽x⩽0.1. The structural and electronic properties of GdxHg1−xSe crystals were investigated as a function of composition. It was found that an increase in gadolinium content up to x=0.01 results in a decrease of structural defects and an increase in electron mobility up to the

IEE Proceedings - Circuits, Devices and Systems, 2005

While magnetoresistive spin valve (SV) layered structures have been widely used in both analogue ... more While magnetoresistive spin valve (SV) layered structures have been widely used in both analogue and digital applications, more recent specular nano-oxide-layer spin valves (NOL-SV) have been used in read head and related digital applications. In the paper, the authors report on the design, fabrication and fundamental characterisation of NOL-SV-based magnetoresistive sensing elements for low-current monitoring purposes. The sensitivity of NOL-SV devices is improved in two ways. On the one hand, NOL-SV structures display higher magnetoresistance levels when compared with standard SVs. On the other hand, the current paths are patterned into the chip during the microelectronics fabrication process, therefore decreasing the gap space between the current paths and the sensing magnetoresistors. The authors describe in detail the fabrication process and characterise the first fabricated prototypes. Currents of the order of 1 mA have proved to be measured. Moreover, the temperature drift and the frequency response of the elements have been measured.

Electrical Isolators Based on Tunneling Magnetoresistance Technology

IEEE Transactions on Magnetics, 2008

Page 1. IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 11, NOVEMBER 2008 4011 Electrical Isolators ... more Page 1. IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 11, NOVEMBER 2008 4011 Electrical Isolators Based on Tunneling Magnetoresistance Technology Càndid Reig 1 , María Dolores Cubells-Beltrán 1 , Diego Ramírez 1 , Susana Cardoso 2 , and Paulo P. Freitas 2 ...

Microelectronics Journal, 2007

In this work, we report on the successfully growing Hg 1Àx Mn x Se bulk crystals using a mixed, t... more In this work, we report on the successfully growing Hg 1Àx Mn x Se bulk crystals using a mixed, travelling heater method and Bridgman method, two-step procedure. Firstly, and with the aim of reducing Hg high pressure related to the high temperature synthesis reaction between the components in elemental form, HgSe crystals were synthesized and grown by the cold travelling heater method. Secondly, previously sublimated Mn and Se were incorporated to complete the desired composition. Then, the Bridgman growth was carried out by heating the alloy at a temperature of about 880 1C and lowering it at rate of 1 mm/h through a gradient of 25 1C/cm. The Hg 1Àx Mn x Se crystals were characterized by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffractometry, Fourier transform infrared spectroscopy and magnetic susceptibility measurements. The summary of the experimental results allows us to be optimistic with the potential of Hg 1Àx Mn x Se as regards using Hg 1Àx Mn x Te and Hg 1Àx Cd x Te for infrared photodetection.

AIP Advances

Neuromorphism is a state-of-the-art paradigm driving the design of many novel devices, including ... more Neuromorphism is a state-of-the-art paradigm driving the design of many novel devices, including sensors. The development of such systems, usually involving the implementation of complex mixed CMOS/sensors chips, is constrained by the lack of compact electrical models compatible with the most utilized design tools. This paper proposes a dynamic compact electrical model specifically conceived for bio-inspired applications of giant magnetoresistance (GMR) based magnetic scanning sensors. The model includes blocks for static analysis, frequency sweeps, and transient simulations. The model, written in Verilog-A high-level language, can be directly used in most of the standard CMOS design platforms, such as Cadence.

We have developed a state-of-the-art surface plasmon resonance imaging (SPRi) apparatus combined ... more We have developed a state-of-the-art surface plasmon resonance imaging (SPRi) apparatus combined with microfluidics and used it to detect the binding of amyloid beta peptides to the lipid membrane, an interaction known to be involved in the molecular mechanism of amyloid toxicity in Alzheimer’s disease, and to study protective effect of melatonin. Kinetics of binding was measured, and quantitative analysis was developed in order to detect melatonin partitioning into and amyloid binding to the membrane. We provided for the first time clear experimental evidence that the presence of melatonin in supported lipid membrane prevents the amyloid peptide from binding to the lipid membrane, thus gaining insight into the molecular mechanism of melatonin protection against amyloid toxicity in Alzheimer’s disease.

Thin Solid Films, 2001

Vapor phase epitaxy VPE of Hg Cd I layers on glass substrates covered by a CdTe buffer layer has ... more Vapor phase epitaxy VPE of Hg Cd I layers on glass substrates covered by a CdTe buffer layer has been studied. The 1yx x 2

Microwave and Optical Technology Letters, 2003

Wideband transitions are designed and analysed by using two different approaches of the finite-di... more Wideband transitions are designed and analysed by using two different approaches of the finite-difference time-domain (FDTD) method, in combination with the theory of nonuniform transmission lines. These transitions consist of a ridged waveguide-based taper between a shielded microstrip and a standard X-band rectangular waveguide. In the first step, a full-wave 2D-FDTD scheme is used to calculate the dispersion characteristics, as well as the geometry dependence of the impedance in the double ridged waveguide. Once these design curves have been obtained, the stepped transmission line transformer theory is used to design the tapers. In a former step, the nonuniform 3D-FDTD technique is applied, the transitions are simulated and the method is validated.

Microwave and Optical Technology Letters, 2005

auxiliary antenna placed at the bottom of the handset terminal. Depending on a mobile system, thi... more auxiliary antenna placed at the bottom of the handset terminal. Depending on a mobile system, this additional antenna enables exploitation of MIMO or the spatial-diversity technique in order to improve radio link quality. The proposed antenna placement in the terminal structure is shown in Figure 8. 672-676. 4. K. Skonieczny, A miniature antenna for handset terminal of 2G 3G cellular mobile systems, Masters thesis,

Microwave and Optical Technology Letters, 2007

The half-moon antenna has been proposed for wideband applications. The half-moon antenna with var... more The half-moon antenna has been proposed for wideband applications. The half-moon antenna with variable tilt angles has been shown to have variable frequency band characteristics. The bandwidth of the proposed antenna is obtained from 1.5 GHz to more than 5 GHz. In this frequency band, omnidirectional radiation patterns have been observed. The radiation patterns are almost immune to the tilt angles. A description of how the proposed antenna gets the wideband operation in this half-moon structure is provided, and required equations are also derived. All the simulation and measured data agree very well with confirming the validity of our theory and the used models. The concept can be simply adapted to design for other antennas operating at different frequency bands.

Microwave and Optical Technology Letters, 1997

The frequency dependence of the characteristic impedance of microstrip lines has been in¨estigate... more The frequency dependence of the characteristic impedance of microstrip lines has been in¨estigated by many authors using 3D-FDTD formulations. In the present letter, a two-dimensional FDTD scheme is used to calculate both the propagation constant and the characteristic impedance of the fundamental quasi-TEM mode in a microstrip which, in fact, is a hybrid mode. Because of the substantial reduction of computer resources required for the calculations, this method can be used as a design tool.