Showing papers by "Blaise Ravelo published in 2019"

Time-Domain Experimentation of NGD ActiveRC-Network Cell

Abstract: A theoretical and experimental investigation of low-pass negative group delay (NGD) topology is introduced. The NGD topology is composed of a low noise amplifier (LNA) and RC-parallel series mounted lumped network. The NGD cell theoretical characterization is elaborated. The NGD properties as NGD level, cut-off frequencies and central frequency are established. The synthesis formulas as function of the expected NGD level and gain are established. The NGD proof of concept using monolithic LNA LEE-9+ manufactured by mini-circuits are designed, simulated, fabricated, and measured. The simulated and measured frequency domain results are in good agreement with the circuit theory. As expected, low-pass NGD behavior is observed with −5 ns-NGD level over 32-MHz bandwidth. The low-pass NGD function meaning is illustrated by the advance of the output pulse signal leading and trailing edges compared to the input ones.

Design of Multi-Scale Negative Group Delay Circuit for Sensors Signal Time-Delay Cancellation

Abstract: This paper develops an innovative method of sensors’ time-delay suppression. The proposed delay cancellation technique is highlighted with a theoretical concept and time-domain experimental demonstrations by using the negative group delay (NGD) function. The analytical investigation is elaborated with an NGD topology constituted by a simple active $RC$ network. It is established theoretically that this active cell behaves like a low-pass NGD topology. The synthesis equations enabling to calculate the NGD cell parameters as a function of the desired NGD and gain are formulated. Frequency- and time-domain analyses showing the NGD function in multi-time scale are discussed. The NGD function verification is fulfilled with the design and fabrication of a proof-of-concept prototype. Nano-, micro-, and milli-second NGD effects are numerically and experimentally proved. As expected, time-domain experimental demonstrations showing arbitrary waveform signal in outstanding time-advance are realized. Moreover, the feasibility of the signal delay cancellation with 1- and 8-m length cables is experimented. The developed NGD time-delay cancellation demonstrations open the potential applications for the sensor performance improvement.

Canonical transfer function of band-pass NGD circuit

Abstract: This study introduces the generalised canonical transfer function (TF) of the band-pass negative group delay (NGD) circuit. The principle to identify the unfamiliar band-pass NGD circuits is suggested. Similar to the filter theory, the band-pass NGD TF can be established from low-pass to band-pass frequency transform. The fundamental characteristics of the NGD topology are described. The canonical TF feasibility is concretised with the second-order equivalent impedance constituted by passive elements. The synthesis formulas in function of the desired NGD level and bandwidth are analytically established. Application examples of band-pass NGD impedance synthesis, designed and fabricated are proposed as a proof of concept. Prototypes of band-pass NGD circuits with centre frequencies 1 and 1.5 MHz for the targeted group delay optimal values, respectively, −1 and −1.5 µs are designed and fabricated. As expected, band-pass NGD results in good agreement with the theoretical prediction were obtained with simple lumped circuits. In the future, thanks to theory simplicity, the NGD band-pass cell can be potentially useful for the signal delay correction.

Fast S-Parameter TAN Model of n-Port Lumped Structures

Abstract: This paper deals with the fast S-parameter modeling of multi-port lumped structures. The developed model is based on unfamiliar formalism using the tensorial analysis of networks (TAN). The modeling methodology is described with the general abstract topology and different application cases. The methodology consists, first, in elaborating the equivalent graph topology of the considered problem. Then, it is followed by the TAN mathematical abstraction, including, successively, the branch and mesh space analyses. The problem metric can be written with the tensorial Ohm's law expressed in function of the covariant voltage, contravariant current, and the twice covariant impedance in the mesh spaces. The equivalent Z-matrix of the considered multi-port structure is established from an innovative reduction method of the mesh impedance. The S-parameter model is extracted from the Z-to-S matrix transform. The effectiveness of the established fast S-parameter TAN modeling is validated with three cases of proof of concept constituted by TT-cell, the TTT-cell two-port circuit, and four-port structure inspired from the 3D coaxial shielded cable. As expected, an excellent agreement between the S-parameters calculated from the TAN model and simulated from the commercial tools from DC to some hundred's megahertz is obtained. In the future, the developed model is outstandingly beneficial for fast and accurate applications notably for the conduced shielded cable electromagnetic compatibility analysis.

Negative Group Delay Theory of a Four-Port RC-Network Feedback Operational Amplifier

Abstract: An innovative negative group delay (NGD) theory based on a unity direct chain feedback (UDCF) circuit topology is developed in this paper. This NGD circuit is an active cell constituted by an operational amplifier in feedback with a four-port RC-network. This NGD circuit theory is developed based on the S-parameter model analytically established from the equivalent impedance matrix. The UDCF group delay frequency response is expressed as a function of the feedback RC-cell and the operational amplifier parameters. The NGD analysis of the developed UDCF cell is introduced. According to theoretical analysis, under a certain condition, the UDCF topology is susceptible to behave as a low-pass NGD function. The UDCF cell NGD characteristics are defined theoretically. The theoretical prediction is verified numerically and experimentally in both the frequency- and time-domain by designing and fabricating an active PCB prototype. The simulations and experimentations show that the UDCF circuit exhibits an NGD of approximately -38 ns with NGD cut-off frequency of about 5.5 MHz. More importantly, it is demonstrated in the time-domain that the low-pass NGD effect enables the UDCF cell to generate advanced output with sinc waveform input voltages.

All-Pass Negative Group Delay Function With Transmission Line Feedback Topology

Abstract: A novel circuit theory of all-pass Negative group delay (NGD) function is investigated. The NGD function is implemented with unity direct chain feedback (UDCF) system. The active circuit is built with an operational amplifier in feedback with a lossy transmission line (TL). The UDCF topology S-parameter model is established versus TL parameters. The NGD analysis is elaborated from the frequency dependent transmission coefficient. The NGD behavior characterization is developed. The synthesis method allowing to determine the UDCF topology parameters in function of the targeted NGD values, gain and reflection coefficient is formulated. The all-pass NGD function is validated with a proof-of-concept (POC) design. Frequency and time domain simulations confirm the feasibility of the innovative all-pass NGD function. With S-parameter analysis, it was shown that the UDCF circuit exhibits NGD up to -7-ns with gain more than 0-dB and reflection coefficient -20-dB. More importantly, time-domain analysis illustrates how the transient tested voltage outputs can be in advance compared to the input.

Multiphysics Tensorial Network Analysis Applied to PCB Interconnect Fatigue Under Thermal Cycle Aggression

Abstract: This paper investigates an original multiphysics KB modeling of the electrothermomechanical (ETM) phenomena in a multi-layer printed circuit board (PCB) under heat cycle aggression. The coupled thermal and intrinsic mechanical interactions with the PCB electrical response are analyzed. The via-interconnect line (IL) junction fatigue caused by the mechanical tensions is explained with tensorial equations. The ETM effects transduced between the PCB components are modeled with equivalent graphs. The multiphysics problem general tensorial relation is formulated. To validate the Kron–Branin model, the numerical application of three-layer PCB proof-of-concept under thermal cycle aggression with 0-to-70 °C variation is introduced. The tensile stresses induced by the thermal effect on the vias and ILs are calculated. The via cracking fatigue model is approximated. The PCB voltage transfer function and input impedance in the function of the thermal aggression are discussed.

Multiphysics Analysis of Pin-Socket Electrical Dynamic Contact Susceptibility Under Vibration Stress

Abstract: The pin-socket connector susceptibility under vibration stress constitutes one of the electrical engineer breakthroughs. Only single electrical engineering is not enough to treat this challenging issue. The Multiphysics analysis is expected to be a solution to analyze this electromechanical dynamic pin-socket structure. This paper develops a dynamic contact Multiphysics analysis with the tensorial analysis of networks (TAN) formalism. The Multiphysics model integrates the pin relative velocity and position coupled with the instantaneous contact resistance implemented in an RC -network. An innovative method enabling to determine the vibration stress signature via the signal-to-noise (SNR) amplitude is established. The relevance of the Multiphysics TAN model is illustrated with an example of a 10-mm-length pin-socket under arbitrary waveform uniaxial vibration stress with 20-kHz bandwidth. It was shown that the contact resistance may fluctuate with more than thousand-time relative variation. More importantly, the vibration stressed pin-socket SNR in function of the RC -network parameters is discussed. The proposed Multiphysics analysis can be potentially applied to the electromagnetic compatibility and signal integrity investigation of assembled electronic equipment and printed circuit boards under vibration stress.

Design, Modeling and Synthesis of Negative Group Delay IL-Shape Topology

Abstract: This paper introduces a negative group delay (NGD) theory of passive topology presenting “IL”-shape geometry. The two-port topology is comprised of a coupled line with an open- and stub-loaded terminations. After introduction of the electrical equivalent circuit, the S-parameter modeling of the IL topology is established. The transmission and reflection parameters are analytically expressed. The IL topology NGD characterization is developed in function of the design parameters. The relevance of the NGD theory is verified with fully distributed and compact prototypes implemented in microstrip technology. The tested results confirm the possibility to generate bandpass NGD function with IL topology. The calculated model, simulation and measurements are in very good correlation. Validation results showing center frequencies at about 1.55 GHz and 3.55 GHz with NGD level better than -1 ns over 30 MHz bandwidth. The IL NGD prototypes present transmission and reflection coefficients better than -3 dB and -10 dB, respectively.

Multiphysics Analysis of Hemispherical Bulk Conductor Hertzian Contact Under Uniaxial Mechanical Load

Abstract: A multiphysics model of smoothed contact surface hemispherical contact under dynamic vibration stress is treated in this paper. The contact structure is applied to hemispherical conductor bulk materials. The structure electrothermomechanical (ETM) behavior is investigated based on the Hertz contact theory coupled with electrokinetic approach. An electrical circuit integrating the contact material properties is proposed. The contact surface deformation ETM expression is formulated. The transient variations of the contact conductor material temperatures in function of the mechanical vibrations are analytically described. The ETM parameters range versus the mechanical load stress is analyzed by considering aluminum alloy material hemispherical bulk with a radius varying from 10 μ m to 1 mm. The contact radius can be totally deformed when the load is increased up to 20 kN. In addition, an innovative multiphysics computational method is validated numerically to determine the transient variation of the contact surface radius model from SPICE simulation by considering 0.5 kHz/1 kHz frequency presenting 0.5-kN amplitude sine wave, and arbitrary waveform dynamic vibrations. It was conjectured from numerical application, the hemispherical bulk contact temperature, and also the mechanism multiphysics phenomena governing the structure behavior. As ongoing research, the equivalent system tensorial statement illustrating the multiphysics interaction between the conductor contacts will be developed.

Modélisation multiphysique : premiers concepts fondamentaux dans le cadre classique

Abstract: L'objet de cet article est de presenter quelques premieres tentatives de modelisation multiphysique basees sur l'analyse tensorielle des reseaux pour realiser des etudes amonts. Nous presentons le formalisme detaille pour considerer un systeme electro-thermo-mecanique. L'objectif est de se doter d'une expression generalisee de la variete associee a un tel systeme. Dans l'approche proposee, la temperature apparait comme un parametre au meme titre que le temps, ces parametres permettent de determiner la courbure de l'espace lorsque les operateurs qui s'appliquent aux flux dependent de la temperature. Nous pouvons noter que ce comportement est tout a fait general au-dela de certaines limites en temperature. Cette affirmation montre que les espaces physiques sont toujours courbes meme dans le cadre de la mecanique classique.

Analysis, design and implementation of a hybrid three-port switchable power splitter (SPWS) on Kapton flexible substrate

Abstract: A topology of switchable power splitter (SPWS) ink-jet printed on flexible Kapton substrate is developed in this paper. The SPWS circuit diagram integrating a Tee PWS is described based on the synoptic approach. The complete theoretical formulations of the SPWS reflection and transmission coefficients were established. The analytical expressions enabling to assess the Tee-PWS elementary output lines for the SPWS input matching are elaborated. To validate the relevance of the proposed SPWS, a proof of concept was synthesized, designed and implemented in microstrip hybrid technology by using the packaged switch biased with 3.3 V DC supply. The fabricated circuit was directly ink-jet printed on a low cost flexible Kapton® polyimide film, using a Dimatix DMP-2831 materials printer. Then, comparisons between the experimental and electromagnetic and circuit co-simulated S-parameters from the SPWS prototype were performed. The measured SPWS performance to operate in the IEEE standard 802.11a bands from 5.4-5.7 GHz was presented. The SPWS presents overall insertion losses of about-5.5 dB and-13 dB respectively for the switches on-and off-state. Furthermore, the input and output return losses are respectively with average value of about-11 dB in the expected operation frequency band.

Synthesis and experimentation of voltage compressor and decompressor with active circuit

Abstract: This paper introduces an innovative circuit theory of analog voltage compressor (AVC) and decompressor (AVD). This electronic function can also be assumed as an analog voltage converter. Analytically, it acts as power function synthesizer topology designed with an analog nonlinear circuit. The AVC/AVD topologies are based on an operational amplifier associated with resistor and non-linear diode components. Given the positive parameter a > 0, the main x-y characteristic of the AVC/AVD is formulated by y = xa for the input and output x and y, respectively. The synthesis formulas allowing to determine the AVC/AVD parameters as a function of a are established. To validate the original AVC/AVD concept, static and dynamic simulations and experimentations with a proof-of-concept circuit using operational amplifier UA741 are carried out. As expected, well correlated x1/2-AVC and x2-AVD characteristics are realized with the static testing for the voltage range varied from 0 to 9-V and 0 to 3-V for AVC and AVD circuits, respectively. The simulation and experimentation of dynamic test results are in good agreement for the sine wave voltages with frequency varied from DC to 1-kHz. The simulated and experimental results confirm the relevance of the developed compressor/decompressor analog circuit. The AVC/AVD functions for instrumentation system applications can be potentially applied to the amplitude matching especially for digital systems.

NGD Synthesizer with Feedback Hybrid Coupler

Abstract: This paper introduces a hybrid coupler based negative group delay (NGD) topology. The NGD circuit is built with a hybrid coupler with one of output and isolated access ways connected in feedback with a lossy transmission line (TL). It is modelled by S-parameter approach. The NGD topology characteristics are formulated. The synthesis relations enabling to determine the NGD circuit parameters in function of the desired NGD value are extracted. Parametric analyses in function of the TL attenuation and time-delay are discussed.

SNR Kron-Branin Model of Shielded Coaxial Cable under Burst Striking

Abstract: This paper develops a Kron-Branin (KB) model of shielded coaxial cable wire structures. The structure is assumed to be struck by kilovolt amplitude high voltage burst. The model is mainly constructed with Kron’s graph and Branin’s transmission line (TL) circuit. The equivalent graph topology of struck shielded cable structure is drawn. The graph consists essentially of branch, mesh, node and cord elements. The tensorial equation transducing the problem under study is reformulated with main unknown the branch currents. The fundamental solutions of the problem are represented by the calculated currents. The analytical expression of the signal-tonoise ratio (SNR) is established in function of the 4-kV amplitude perturbation strike with 5-V amplitude and 1-Gbps rate square wave data. A good correlation between analytical modeled and simulated SNRs from 50-MHz to 0.55-GHz is obtained.

Water Wave Micro-Energy Mini-Boat Harvester

Abstract: This paper introduces an original research work on experimental demonstration of micro-energy harvesting from water wave. To implement this demonstrator, commercial piezo-electric elements are used as an electromechanical aquatic energy transducer. The proof-of-concept is constituted by electrical micro-energy sensor circuit implemented on a mini-boat external surface. The water wave is generated by the valve oscillating motion placed in a water tank. Because of the wave interaction with the piezo, it was shown that the electrical circuit placed on the micro-boat surface generates instantaneous electrical power with microwatt amplitude under some Volts amplitude instantaneous voltage. The influence of the boat orientation in function of the water wave propagation direction is investigated.

NGD Circuit Design with Coupled Line EMI

Abstract: This paper introduces a bandpass NGD function with EMI effect between neighbored lines. After the topological brief description of the structure, the S-parameter model is presented. An NGD analysis is performed in function of the topological parameters. The bandpass NGD function is approved with a fully distributed NGD proof-of-concept. The equivalent model, simulation and measurement results are in good agreement. The experimental results show an NGD level, center frequency and bandwidth of about (-2 ns, 1.71 GHz, 35 MHz), respectively, with a good performance in terms of attenuation and reflection losses.