Showing papers by "Blaise Ravelo published in 2015"

PCB Near-Field Transient Emission Time-Domain Model

Abstract: This study is aimed at the time-domain (TD) electromagnetic compatibility (EMC) modeling of a planar near-field (NF) emission. The radiated EMC model is built, consisting of elementary dipole array, capable of accurate reproduction of NFs emitted by electronic circuits with transient excitations of nanoseconds duration. The details of the modeling approach are explained. The determination method of dipole parameters from the given time-dependent scanned 3-D electromagnetic (EM) field is developed. The proposed TD model was validated first with ideal sources excited by electrostatic discharge standard surge currents. Then, it was validated with the experimental scanned magnetic NF radiated by a microstrip circuit excited by a pulse RF signal. The magnetic field predictions confirmed the modeling procedure correctness. Modeling errors in reproducing the scanned transient 3-D EM field were better than 0.1%. Errors in NF to NF transformation of the transient EM field were in the range of 2%. The suggested model is particularly useful for the EMC NF emission investigation of modern multifunctional electronic systems with a mixture of analogue and digital blocks generating transient and impulse disturbances.

Effect of high spin Mn2+ /Mn3+ ions on microstructural, optical, magnetic and electrical properties of hydrothermally prepared Ni–Mg nanoferrites

Abstract: A nanoferrite series of composition Ni0.5−xMnxMg0.5Fe2O4 with x = 0, 0.1, 0.2, 0.3 and 0.4 has been prepared by a hydrothermal method. X-ray diffraction (XRD) confirmed the formation of cubic spinel structure. The average crystallite size is found to be in the range of 28–48 nm. The lattice parameter is found to increase linearly with an increase in Mn2+ content. Field Emission Scanning Electron Microscopy micrographs indicate that the samples have almost uniform sized crystallites with uniform grain growth. Fourier Transform Infrared (FTIR) Spectroscopy studies showed two absorption bands close to 603 and 400cm−1 for the tetrahedral and octahedral sites respectively. Saturation magnetization attained a maximum value of 34.15 emu/g at x = 0.3 and then decreases for higher concentrations of Mn2+ ions. Activation energy for compositions Ni0.3Mn0.2Mg0.5Fe2O4 and Ni0.2Mn0.3Mg0.5Fe2O4 are found to be 0.371 eV and 0.471 eV, respectively. For composition Ni0.2Mn0.3Mg0.5Fe2O4, maximum value of observed density, minimum porosity, maximum value of saturation magnetization, maximum initial permeability and minimum value of coercivity is obtained. DC resistivity is found to be of the order of 108Ωcm. The obtained results have been explained based on possible mechanisms, models and theories.

Modelling of asymmetrical interconnect T-tree laminated on flexible substrate

Abstract: A fast and accurate behavioral modelling of asymmetrical microstrip tree printed on plastic substrate is investigated. The methodology for extracting the asymmetrical tree transfer responses based on the ABCD-matrix analysis is presented. The elements of the interconnect T-tree are constituted by transmission lines (TLs) defined by their characteristic impedance and physical length. The distributed tree network can be assumed as a single input multiple output (SIMO) topology. By considering the circuit equivalent between the electrical path from the tree input and output, the single input single output (SISO) simplified circuit can be established. In order to determine the frequency response of the interconnect tree system, the elementary TLs constituting the tree branches are modelled with their equivalent frequency dependent RLCG network. The novelty of the present paper is the application of the model to the microstrip structure printed on the plastic substrate by analyzing the influence of the metallization conductivity. As proof of concept (POC), a single input and three output distributed interconnect T-tree having branches presented physical lengths from 3 cm to 20 cm was designed. The POC was printed on the Cu metal deposited plastic Kapton substrate. Then, the frequency dependent per unit length resistance, inductance, capacitance and conductance of the elementary branches of the T-tree from DC to 10 GHz were extracted. By implementing the behavioral model of the circuit, the frequency- and time-domain responses of the proposed asymmetrical T-tree are computed. Then, the analyses of the asymmetrical T-tree responses in function of the thin film conductivity of the microstrip interconnect lines were discussed. In addition, time domain analysis enabling to predict the influence of the deposited metallic ink conductivity on the signal integrity is realized by considering a mixed signal corresponding to the digital data “010110000” having 0.5 Gbps rate. Moreover, the signal integrity through the asymmetrical T-tree was also performed with eye diagram. A considerable attenuation and signal delay were occurred due to the roughness and impurities of the copper interconnect ink.

Microstrip Dielectric Substrate Material Characterization with Temperature Effect

Abstract: This paper describes a dielectric substrate materials electromagnetic (EM) characterization method in the ultra-wideband (UWB) frequencies from DC to 5 GHz by taking into account the temperature influence. The proposed method theoretical principle is described and fundamentally built with the analytical formulation from the microstrip transmission line (TL) theory. From this basic concept, the analytical equations enabling to determine the dielectric material relative permittivity and loss tangent from the given S-parameters are established. The characterization method is validated with numerical and experimental tests. As proof of concept, a prototype of microstrip TL printed on FR4 epoxy substrate was designed, fabricated and experimented. The relative permittivity and loss tangent were extracted in the UWB frequency from DC to 5 GHz in the range of temperature varied from 40°C to 140°C. This innovative characterization method is useful for the investigation on the frequency dependent and especially by taking into account the temperature influence on the substrate materials; for example, during the microstrip circuits design phase.

Radiated EMC immunity investigation of common recognition identification platform for medical applications

Abstract: An innovative e-healthcare platform named common recognition and identification platform (CRIP) was developed and tested as part of the CareStore project. CareStore and CRIP aims at delivering accurate and safe disease management by minimising human operator errors in hospitals and care facilities. To support this, the CRIP platform features fingerprint biometrics and near field communication (NFC) for user identification; and Bluetooth communication support for a range of telemedicine medical devices adhering to the IEEE 11073 standard. The aim of this study was to evaluate the electromagnetic compatibility (EMC) immunity of the CRIP platform in order to validate it for medical application use. The first prototype of CRIP was demonstrated to operate as expected by showing the user identification function feasibility, both via NFC and biometric, and by detection of Bluetooth devices via radio frequency (RF) scanning. The NFC module works in the 13.56 MHz band and the Bluetooth module work in the 2.4 GHz band, according to the IEEE 802.15.1 standard. The standard test qualification of the CRIP was performed based on the radiated EMC immunity with respect to the EN 61000-4-3 standard. The immunity tests were conducted under industrial EMC compliance with electric field aggression, with levels up to 10 V/m in both horizontal and vertical polarisations when the test antenna and the CRIP were placed at a distance of 3 m. It was found that the CRIP device complies with the European electromagnetic (EM) radiation immunity requirements.

Wireless authentication platform for healthcare applications

Abstract: An innovative wireless authentication platform for healthcare applications is designed, implemented and tested It acts as a Common Recognition and Identification Platform (CRIP) operating with write/read function via either NFC or biometric modules for the users' authentication The CRIP base station architecture consists of 1356MHz NFC/RFID and 24GHz IEEE standard 802151 BLE modules The Bluetooth function enables the medical device communication with the tens meter range RF link The CRIP prototype was tested successfully in hospital environments The blood pressure data transmission in real time was collected and monitored with an assistant living healthcare platform Finally, the CRIP complies in conformity with the electromagnetic compatibility (EMC) standard EN55022 Class B requirements

Radiated Near-Field Emission Extraction on 3D Curvilinear Surfaces from 2D Data

Abstract: This paper deals with a fast and simple computational method of 3D near-field (NF) radiation from 2D planar frequency- and time-dependent data. The established calculation method can be used to predict the electromagnetic (EM) emission from various types of electronic devices. The proposed method is originally applicable to the computation of the EM NF along the arbitrary shaped curvilinear 3D surface of multi-shape objects. The EM computation consists in the application of the planar NF-to-NF transform using plane wave spectrum. The relevance of the established method is verified with three different validation tests of analytical and practical demonstrations. The first validation is based on the analytical NF radiation from set of elementary dipoles excited by a harmonic signal. The second validation test is based on the experimented data from a hybrid active printed circuit boards (PCBs) in the frequency domain. The last validation test is performed with the measured NF data from a microstrip planar circuit in the time-domain. For all the different test cases, the plots of EM NF on arbitrary curvilinear surfaces are presented. Applications with 3D visualization or holographic surface with arbitrary geometry of EM radiation from planar data in both frequency- and time-domains confirm the effectiveness of the proposed method to predict the EM NF emission from complex PCBs. The developed 2D-to-3D computational method is particularly useful for radiated EM compatibility engineering.

Design of 5GHz switched power splitter on organic flexible substrate

Abstract: A microstrip 1∶4 switched power splitter (SPWS) printed on flexible Kapton substrate is designed. The SPWS topology is designed and implemented in hybrid technology by using the packaged switch SKY13298-360LF biased with 1.8 V supply. Electromagnetic and circuit co-simulations confirm the SPWS performance to operate in the IEEE standard 802.11a bands from 5.470–5.725 GHz. The designed 1∶4 SPWS presents −3.5 dB and −30 dB insertion losses were evaluated respectively for the on- and off-state branches. Furthermore, the input and output return losses are respectively of about −17 dB and −15 dB. This flexible SPWS can be potentially used to design switched beam steering wireless system.

RF transient pulse signal integrity with ns-duration for atom-probe tomography

Abstract: Improvement of atom probe tomography requires the high voltage rectangular short pulses. This typical RF transient pulse must be applied on a sample inside an ultra-high vacuum (UHV) chamber. In this letter, we present a synthesis technique of rectangular pulse signal with full width ns-duration. The pulse signal was injected into the cryogenic analysis chamber through the transmitting system composed of a microstrip transmission line. The system frequency characterization based on the S-parameter analysis and RF engineering shows the transmitting system major deterrent. The preliminary experimental result demonstrates that the atom probe performance is improved.

Electrical predictive model of Zener diode under pulsed EOS

Abstract: Electrical overstress (EOS) is assumed as one of the most misinterpreted electrical phenomena that can affect drastically the reliability of electronic components. To predict the behaviour of a circuit under EOS, a relevant predictive circuit model is required. An investigation of circuit degradation caused by the pulsed EOS is addressed. More precisely, the electrical response of the Zener diode BZX84B6V8 under square wave EOS is modelled. The proposed model is originally extracted from the diode electro-thermal behaviour caused by the self-heating induced by excessive EOS on the reverse voltage. The diode EOS model was emulated and implemented in VHDL-AMS language. It has been found experimentally, with a 17 V amplitude and 8 ms period square wave EOS, that the diode transient electrical parameters enable experimental response prediction. The suggested model can be used for reliability analyses of electronic devices.

RF and EMC investigation on CRIP system for the e-healthcare CareStore platform

Abstract: This paper is aimed to the RF coverage and electromagnetic compatibility (EMC) analyses of e-healthcare CareStore platform. The functioning principle of this innovative platform is described. Its RF hardware part named CRIP platform is composed of 2.4GHz BLE112 Bluetooth and NFCRFID (ISO/IEC-18092) and biometrics (ISO/IEC-19794) readers as identification functions. The RF coverage of the CRIP Bluetooth antenna system in the indoor wireless communication scenario of multi-wall floor was investigated based on the multipath channel propagation ITU model. Then, the EMC qualification test results were presented with respect to the EU conformity with IEC/EN55022 for the emission and IEC/EN61000-3-4 for the radiated immunity. It was shown that the first version of CRIP device operates correctly under the EM radiation expected with this standard. However, further improvement will be made on the second version of the CRIP by including WLAN Wi-Fi function. This version should take into account the software interface allowing to assure the healthcare data storage via could system. With this second version, the hardware circuit boards will be implemented in order to minimize the EM radiation outside the operating frequency bands.

Analysis of a Healthcare Platform RF Emission in Indoor Environment

Abstract: The paper investigates the Radio Frequency (RF) coverage and electromagnetic interference (EMI) effect on the performance of the e-healthcare platform CareStore. The hardware part is constituted by the Common Recognition and Identification Platform (CRIP) which operates with Bluetooth in order to detect and receive data from medical devices. To assess the CRIP board performance against the EMIs, the symbol-error-rate (SER) is evaluated in function of the signal-interference-noise-ratio (SINR) and with various digital data modulation techniques. As expected, the SER increases with the SINR and decreases with the number of bits/symbol. Furthermore, the RF link budgets and the unintentional EMIs were analyzed based on Matlab computations by considering an equivalent transmitter source placed in a multiwall floor environment with dimensions of hundreds square meters. The received signal strength coverage cartographies were established for ideal sources placed at different locations. The proposed method benefits from its simplicity and high computation speed compared to the ray tracing or full wave approaches. Keywords-multiwall indoor environment, wireless device, electromagnetic interference (EMI), RF coverage cartography.