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Search Results: 1 - 10 of 420 matches for " Blaise Ravelo "
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Investigation on the Microwave Pulse Signal Compression with Ngd Circuit
Blaise Ravelo
PIER C , 2011, DOI: 10.2528/PIERC10122305
Abstract: This paper demonstrates the exhibition of pulse compression from an electronic circuit with negative group delay (NGD). This circuit consists of a field effect transistor (FET) cascaded with shunt RLC network. Theoretic and experimental investigations have proved that, at its resonance frequency, the group delay of this circuit is always negative. The present study shows that around this resonance, it presents a gain form enabling to generate pulse compression. To validate this concept, as proof-of-principle, devices with one- and two-stages FET were implemented and tested. Measurements of the one-stage test device evidenced an NGD of about -2.5 ns and simultaneously with 2 dB amplification operating at 622 MHz resonance frequency. In the frequency domain, in the case of a Gaussian input pulse with 40\,MHz frequency standard deviation, this resulted in 125% expansion of pulse width compared to the input one. In time domain, simulations showed that the compression was about 80% in the case of an input Gaussian pulse with 4 ns standard deviation. With the other prototype comprised of two-stage NGD cell, the use of a sine carrier of about 1.03 GHz allowed to achieve 87% pulse width compression.
Behavioral Model of Symmetrical Multi-Level T-Tree Interconnects
Blaise Ravelo
PIER B , 2012, DOI: 10.2528/PIERB12040205
Abstract: An accurate and behavioral modeling method of symmetrical T-tree interconnect network is successfully investigated in this paper. The T-tree network topology understudy is consisted of elementary lumped L-cells formed by series impedance and parallel admittance. It is demonstrated how the input-output signal paths of this single input multiple output (SIMO) tree network can be reduced to single input single output (SISO) network composed of L-cells in cascade. The literal expressions of the currents, the input impedances and the voltage transfer function of the T-tree electrical interconnect via elementary transfer matrix products are determined. Thus, the exact expression of the multi-level behavioral T-tree transfer function is established. The routine algorithm developed was implemented in Matlab programs. As application of the developed modeling method, the analysis of T-tree topology comprised of different and identical RLC-cells is conducted. To demonstrate the relevance of the model established, lumped RLC T-tree networks with different levels for the microelectronic interconnect application are designed and simulated. The work flow illustrating the guideline for the application of the routine algorithm summarizing the modeling method is proposed. Then, 3D-microstrip T-tree interconnects with width 0.1 μm and length 3 mm printed on FR4-substrate were considered. As results, very good agreement between the results from the reduced behavioral model proposed and SPICE-computations is found both in frequency- and time-domains by considering arbitrary binary sequence ''01001100" with 2 Gsym/s rate. The model proposed in this paper presents significant benefits in terms of flexibility and very less computation times. It can be used during the design process of the PCB and the microelectronic circuits for the signal integrity prediction. In the continuation of this work, the modeling of clock T-tree interconnects for packaging systems composed of distributed elements using an analogue process is in progress.
E-Field Extraction from H-Near-Field in Time-Domain by Using Pws Method
Blaise Ravelo
PIER B , 2010, DOI: 10.2528/PIERB10071307
Abstract: A novel technique of the electric- or E- field extraction from the magnetic- or H- near-field in timedomain is reported. This technique is based on the use of the Maxwell-Ampere relation associated to the plane wave spectrum (PWS) transform. It is useful for the E-near-field computations and measurements which are practically complicated in time-domain in particular, for the EMC applications. The considered EM-field radiation is generated by a set of electric dipoles excited by an ultra-short duration current having frequency bandwidth of about 10-GHz. The presented EM-field calculation technique is carried out by taking into account the evanescent wave effects. In the first step, the time-dependent H-field data mapped in 2-D plan placed at the height above the radiating devices are transposed in frequency-dependent data through the fast Fourier transform. In order to respect the near-field approach, the arbitrary distance between the EM-field mapping plan and radiating source plan should be below one-sixth of the excitation signal minimal wavelength. In the second step, one applies the PWS transform to the obtained frequency-data. Then, through the Maxwell-Ampere relation, one can extract the E-field from the calculated PWS of the H-field. In the last step, the inverse fast Fourier transform of the obtained E-field gives the expected time-dependent results. The relevance of the proposed technique was confirmed by considering a set of five dipole sources placed arbitrarily in the horizontal plan equated by z = 0 and excited by a pulse current having amplitude of 50 mA and half-width of about 0.6 ns. As expected, by using the , and 2-D data calculated with Matlab in the rectangular plan placed at = 3 mm and = 5 mm above the radiating source, it was demonstrated that with the proposed technique, one can determine the three components of the E-field , and .
Characterization of the Regular Polygonal Waveguide for the RF EM Shielding Application
Blaise Ravelo;Belahcene Mazari
PIER M , 2010, DOI: 10.2528/PIERM10030306
Abstract: This article presents a theoretical characterization of the regular polygonal waveguide (RPW) having n-sides. Based on the symmetrical circular symmetry of the RPW and the circular waveguide (CW), the analogy between the electromagnetic (EM) behaviors of these to waveguide (WG) is established. After a brief recall about the state of the art concerning the WG engineering and its application, we introduce a basic theory of the WG presenting a regular polygonal cross-section with -sides. By considering, the fundamental mode , we develop the main mathematical formulas summarizing the different characteristics (cut-off frequency, , propagating constant, and S-parameters) appropriated to any RPW in function of its physical parameters (number of sides, , diameter, and height, ). In order to verify the validation of the developed analytical expressions, comparisons between the HFSS simulated and theoretical dispersion diagrams of regular pentagonal (=5), hexagonal (=6), heptagonal (=5) metallic (copper) WG with for example, 50 mm outer diameter are presented. So, it was demonstrated that very good correlation between the theoretical predictions ((), ()) is found with a relative error less than 1%. As application of the present study in terms of EM wave shielding, simulation of metallic wall with hexagonal aperture is also performed. Finally, discussion about the future work is drawn in conclusion.
Numerical Modeling of High-speed Microelectronic Interconnects for the Signal Integrity Analysis
Blaise Ravelo,Lala Rajaoarisoa
International Journal of Emerging Sciences , 2013,
Abstract: Facing to the incessant increase of data processing speed, the microelectronic interconnections play an important role during the design of the integrated system. As the interconnection signal delays dominate widely gate delays, accurate interconnection model is needed. Indeed, direct mathematical calculation of distributed interconnection transient responses is generally very complicated. For this reason, one proposes to develop a numerical modeling method of prediction of the signal integrity (SI) propagating though the distributed interconnection lines. For that, the microelectronic interconnect lines are assumed as comprised of periodical lumped L-cells cascaded. Via L-cell transfer matrix analysis, it is established how to determine the equivalent global transfer function versus the lumped cell element number n. To verify the relevance of developed model, RC-line with mm-length excited by square-wave-pulse with 10 Gbits/s rate was investigated in function of n and the interconnect line per unit length parameters. As results, transient responses perfectly well-correlated to the SPICE-computations were found with relative errors lower than 5% for n higher than 20. In addition, values of propagation delays and signal attenuations closed to SPICE-models were evidenced for various interconnection network parameters. The computation-time for the execution of the proposed method algorithm was only of tens μs.
Application of Near-Field Emission Processing for Microwave Circuits under Ultra-Short Duration Perturbations
Yang Liu,Blaise Ravelo
Advanced Electromagnetics , 2012, DOI: 10.7716/aem.v1i3.11
Abstract: This paper is dealing with a time-frequency modeling method of electromagnetic (EM) near-field (NF) radiated by electronic devices excited by transient pulse signals. The model developed enables to calculate the EM NF maps at different distances from the given device and also the synthesis of radiation sources enabling to reproduce the field maps. The method proposed is based on the ultra wide band (UWB) frequency model of EM NF maps. The number of EM NF maps can be reduced by considering an innovative algorithm in order to establish simply the dipole model. Then, the transient model can be realized by considering the convolution between the transient excitation signals and the dipole-array model. The method proposed was validated by a standard 3D EM tool with a planar microstrip device excited by microwave signal modulating 1.25-GHz-carrier with 0.5-GHz-bandwidth. As expected, good correlation is found between results from simulation and the investigated modelling method. The method introduced in this paper is particularly useful for the investigation of time-domain emissions for EMC applications by considering transient EM interferences (EMIs).
Cancellation of Delays in the High-Rate Interconnects with UWB NGD Active Cells
Thomas Eudes,Blaise Ravelo
Applied Physics Research , 2011, DOI: 10.5539/apr.v3n2p81
Abstract: This paper is devoted to the extension of the interconnect effect equalization concept with NGD circuits for UWB applications. First, RC interconnect effects are considered. It was found that by cascading with the NGD structure, the propagation delay of the considered rate 4 Gbps signal was compensated for about 98-%. Then, the feasibility of the technique by taking into account the interconnection inductive effect with RLC-model is also investigated. It was demonstrated that the technique proposed brings opportunities to compensate for simultaneously the propagation delay and distortions. Then, the application of the proposed technique for the optical interconnect correction is discussed.
An FET-based microwave active circuit with dual-band negative group delay
Ravelo, Blaise;De Blasi, Serge;
Journal of Microwaves, Optoelectronics and Electromagnetic Applications , 2011, DOI: 10.1590/S2179-10742011000200006
Abstract: recent studies proved that certain electronic active circuits are capable to exhibit simultaneously a negative group delay (ngd) and amplification in microwave frequency bands. one of the simplest topologies generating this counterintuitive ngd function effect is formed by a series rlc-network in cascade with a transistor. by using this cell, similar to the classical electronic functions, dual-band ngd microwave devices with loss compensation possibility can be designed. theoretic demonstrations concerning the theory of the ngd circuit considered are presented. the dual-band ngd concept feasibility is concretely illustrated by an example of em/circuit co-simulations. so, in frequency domain, dual-band ngd with minimal values of about -1 ns was observed simultaneously within two frequency bands centered at about 1.05 ghz and 2.05 ghz. to highlight the functioning of the hybrid device considered, time-domain analysis showing the rf/microwave signal advancement is performed. as application, the concept investigated can be envisaged for data synchronization in multi-channel wireless communication systems eventually degraded by undesired emi effects.
Thermal Effect Modeling on Passive Circuits with Mlp Neural Network for Emc Application
Mohamed Bensetti;Fabrice Duval;Blaise Ravelo
PIER M , 2011, DOI: 10.2528/PIERM11042602
Abstract: During the last two decades, several simulation tools have been proposed for the modeling of electronic equipments in function of the physical environmental changes. It was stated that numerous electronic components such as semiconductor devices can be affected by the mechanistic effects, humidity or simply the temperature variations. To study the last effect, based on the multilayer perceptron neural network (MLPNN), a characterization method of the passive electronic device thermal effects is introduced in this paper. The method proposed was realized toward the equivalent circuit identification of the under test device (R, L, C components) measured input impedances. To demonstrate the relevance of the method, numerical computations with MLPNN algorithms implemented into Matlab were performed. First, a capacitor modeling from 30 kHz to 1 GHz for the temperature variation from 25°C to 130°C is presented. It was found that a good agreement between the proposed model and the measurement is observed. Then, a commercial EMI low-pass filter was also characterized in RF frequencies through the S-parameter identification. Finally, further discussion on the potential applications of this work, in particular, in the electromagnetic compatibility (EMC) field is offered in the last part of this paper.
Transient Response Characterization of the High-Speed Interconnection Rlcg-Model for the Signal Integrity Analysis
Thomas Eudes;Blaise Ravelo;Anne Louis
PIER , 2011, DOI: 10.2528/PIER10111805
Abstract: This paper is devoted on the characterization method of RF/digital PCB interconnections for the prediction of the high-speed signal transient responses. The introduced method is based on the use of the interconnection line RLCG-model. Theoretical formulae enabling the extraction of the electrical per-unit length parameters R, L, C and G in function of the interconnection line physical characteristics (width, length, metal conductivity, dielectric permittivity ...) are established. Then, by considering the second order approximation of the interconnection RLCG-model transfer matrix, the calculation process of the transient responses from the interconnection system transfer function is originally established. To demonstrate the relevance of the proposed model, microwave-digital interconnection structure comprised of millimetre microstrip line driven and loaded by logic gates which are respectively modelled by their input and output impedances was considered. Then, comparisons between the SPICE-computation results and those obtained from the proposed analytical model implemented in Matlab were made. As results, by considering a periodical square microwave-digital excitation signal with 2 Gbits/s rate, transient responses which are very well-correlated to the SPICE-results and showing the degradation of the tested signal fidelity are observed. The numerical computations confirm that the proposed modelling method enables also to evaluate accurately the transient signal parameters as the rise-/fall-times and the 50% propagation delay in very less computation time. For this reason, this analytical-numerical modelling method is potentially interesting for the analysis of the signal integrity which propagates in the high-speed complex interconnection systems as the clock tree distribution networks. In the continuation of this work, we would like to apply the proposed modelling process for the enhancement of signal quality degraded by the RF/digital circuit board interconnection where the signal delays and losses became considerably critical.
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