Showing papers by "Blaise Ravelo published in 2020"

Manganese Zinc Ferrites: a Short Review on Synthesis and Characterization

Abstract: Manganese zinc ferrites are technically and scientifically a very important class of ferrite materials because they possess a very high magnetic permeability and low core losses. These materials have been broadly used in electronic applications such as transformers, choke coils, noise filters, and memory devices. Extensive research has taken place and still going in this field of science and technology. Applications of Mn-Zn ferrites in last 10 years are reviewed. General features, properties, and applications are discussed. Also, the various synthesis techniques used for the preparation of Mn-Zn ferrites are also considered such as normal ceramic technique, sol-gel method, hydrothermal method, co-precipitation method, and citrate precursor method. As the field is quite large, a reasonable effort has been made to include some of the original references discussing in details the specific outcome of the papers published.

Analytical Design of Dual-Band Negative Group Delay Circuit With Multi-Coupled Lines

Abstract: This paper develops an innovative design method of a multi-coupled line (CL) topology of low-loss dual band negative group delay (NGD) circuit. The proposed is conceived using three transmission lines (TLs) with different length in which integrate two couplers. The three traveling paths are designed to generate the dual-band NGD effect, where the CLs allow lowering the signal attenuation. The NGD circuit S-parameter model as a function of the TLs physical lengths and coupling coefficient are established. To validate the NGD circuit proof-of-concept, it is fabricated and measured. The NGD values of approximately -4.06 ns and -3.83 ns are measured at center frequencies of 2.43 GHz and 3.02 GHz, respectively. The measured transmission coefficient is better than -2.9 dB and the measured reflection one is better than -12 dB into the NGD band. The measurement results of the NGD circuit are in good agreement with the simulations results.

O=O Shape Low-Loss Negative Group Delay Microstrip Circuit

Abstract: This brief deals with an innovative design of negative group delay (NGD) topology presenting O=O geometrical shape. This fully distributed NGD topology is composed of a power divider (PWD), power combiner (PWC) and coupled line (CL) built with lossy and delayed transmission lines (TLs). The PWD and PWC are connected via the CL. By using 3-port PWD and PWC, 4-port CL S-matrices, the O=O topology model allowing to determine the group delay (GD) is established. To verify the NGD aspect of the O=O topology, parametric analyses with respect to TL characteristic impedance and delay are performed. In addition, a microstrip circuit prototype is designed, simulated and measured. A good NGD performance with NGD level of approximately −2.8 ns around the center frequencies 1.2 GHz with transmission coefficient of approximately −2.2dB and reflection coefficient better than −15dB. The measured results are in very good agreement with calculated model and simulations.

Analysis of Interconnect Line Coupled With a Radial-Stub Terminated Negative Group Delay Circuit

Abstract: This article introduces a negative group delay (NGD) analysis of interconnect line coupled with a radial stub terminated line. The NGD topology equivalent model is established by considering the microstrip interconnect line and radial stub circuits. The S-parameter and the group delay are expressed as a function of NGD fully distributed topology parameters. The NGD optimal frequencies and existence condition are originally established as a function of the coupler and the associated RLC -network parameters. It was innovatively shown that the proposed NGD circuit presents a property to generate double NGD center frequency. A proof-of-concept designed and implemented in the microstrip technology was simulated and fabricated to validate the NGD concept. Simulated and measured results are in good correlation with the NGD theoretical prediction. The prototype test results confirm the NGD characteristics as −2.1 ns NGD level at the 1.34-GHz center frequency over 56-MHz bandwidth.

Reconstruction Technique of Distorted Sensor Signals With Low-Pass NGD Function

Abstract: This paper develops a new reconstruction technique of undesirable signal distortion generated by sensor electronic circuits. The introduced reconstruction technique is originally realized with unfamiliar low-pass negative group delay (NGD) function. The feasibility condition of the proposed reconstruction technique in function of the sensor signal spectrum bandwidth under consideration is elaborated. The reconstruction technique principle is theoretically introduced by means of identification of low-pass NGD function parameters and the appropriated circuit topology. The unfamiliar low-pass NGD function analysis and synthesis equations are established. As an example, for the feasibility study, an RC-network based low-pass active cell is considered to implement the low-pass NGD function. A design method of NGD circuit in function of the sensor distortion transfer function is described in different successive steps. The developed NGD reconstruction technique is validated by different proofs of concept. First, transient simulations are carried out with Gaussian and sinc analytical signals. Then, experimental feasibility study is also performed with arbitrary waveform signal. As expected, the NGD reconstruction technique efficiency is confirmed with improvement of distorted signal integrity parameters and cross correlation better than 97%.

Negative Group Delay Theory on Li Topology

Abstract: This paper investigates an innovative negative group delay (NGD) theory of “li” geometrical shape topology. The li-topology is an outstandingly simple and fully distributed circuit comprised of a coupled line (CL). The li S-parameter model taking into account the CL coupling coefficient, delay and attenuation is established. The NGD analysis showing the possibility to generate NGD condition with respect to the li topology parameters is developed. The NGD characteristics as NGD value, center frequency, bandwidth, transmission and reflection coefficient are expressed. The li-NGD theory is validated with two proofs-of-concept implemented in microstrip technology. Calculated models, simulations and measurements are in good correlation. As expected, bandpass NGD presenting center frequency at approximately 2.56 GHz and 0.92 GHz with NGD level of approximately −0.9 ns and −3.7 ns were realized with the small and large li prototypes. Outstanding time-domain analyses explaining the bandpass NGD meaning, with innovatively low attenuation output, were also presented. The time-domain results highlight li-output pulse signal envelopes in time advance without violating the causality.

Low-Pass NGD Voice Signal Sensoring With Passive Circuit

Abstract: Nowadays, the speech signal processing is still challenging with the multimedia ubiquity. Classical signal processing techniques as filtering were developed for the speech enhancement to overcome unintentional effects as the propagation channel. However, the delay effect remains an open challenge for audio signal processing engineers. A voice/song signal (VSS) prediction is investigated theoretically and experimentally in this paper. This VSS engineering allows to predict an arbitrary waveform signal by using a lowpass negative group delay (NGD) function. This outstanding function presents the VSS advance properties when its parameters are matched with the operated signals. This NGD engineering analytical approach is described with the audio signal processing. The low-pass NGD analysis and property are deeply investigated with two NGD RC-and RL-passive cells. NGD transient study is performed with parametric analytical signals presenting raised cosine waveform. The introduced VSS NGD sensoring is verified with experimental real-time tests of microphone VSS generator. VSS time-advance of approximately 50 μs was observed with a good agreement between simulations and measurements.

0IO-Shape PCB Trace Negative Group-Delay Analysis

Abstract: This paper elaborates a negative group delay (NGD) analysis of 0IO-shape printed circuit board (PCB) traces. This circuit topology is originally implemented with a tri-coupled line (3CL) six-port element with the lateral side connected through lossy transmission lines (TLs). After description of the electrical equivalent diagram, the S-matrix model is established. The group delay (GD) is formulated from the transmission coefficient as a function of the 0IO topological parameters. The effectiveness of the GD modelling is verified with a microstrip circuit proof-of-concept (POC). Simulations and measurements, which are in good agreement, confirm the dual-band bandpass NGD behavior of the 0IO POC. The fabricated prototype generates NGD levels better than −1 ns at NGD center frequencies of about 2.2 GHz and 3 GHz. In addition, to this good NGD performance, the 0IO POC operates with a low insertion loss better than 2.5 dB and reflection losses better than 12 dB in the NGD bandwidths.

Original Theory of NGD Low Pass-High Pass Composite Function for Designing Inductorless BP NGD Lumped Circuit

Abstract: This paper aims to develop an original circuit theory of inductorless NGD topology. The considered passive cell comprised of resistor and capacitor elements without inductor operates as a bandpass (BP) NGD function. The specifications of NGD functions are defined. Generally, the BP NGD fully lumped circuits available in the literature operate with resonant RLC-network. In the introduced research work, a lumped circuit was first time identified to exhibit the BP behavior without the presence of inductive component. The inductorless BP NGD topology is inspired from the combination of low-pass (LP) and high-pass (HP) NGD passive cells. Therefore, an original LP-HP NGD composite topology is obtained. The identified BP NGD topology is constituted only by passive RC-networks. Then, theoretical development of BP NGD analysis is explored. The inductorless circuit theory starts with the identification of BP NGD canonical form. Then, the expressions of NGD value, center frequency and attenuation in function of RC-network parameters are established. The synthesis equations allowing to determine the resistor and capacitor elements are derived. Proofs-of-concept are designed and prototypes are fabricated to verify the effectiveness of the developed LP-HP NGD composite theory. To validate the developed original circuit theory, two prototypes of RC-network based LP-HP NGD composite were designed, fabricated, simulated and tested. The two prototypes were synthesized with respect to two different NGD center frequencies 13.5 MHz and 22 MHz. As expected, the calculated, simulated and measurement results are in very good agreement with NGD value of about some negative nanoseconds. In the future, the characterized inductorless topology enable to overcome the traditional limitations of RLC-network based BP NGD circuits because of inductance self-effect limitation.

Radiated EMC Kron's Model of 3-D Multilayer PCB Aggressed by Broadband Disturbance

Abstract: This paper focuses on novel modeling of radiated electromagnetic compatibility (EMC) coupling onto the multilayer printed circuit board (PCB). Kron's method integrates the electromagnetic (EM) emission, Taylor's, and field-to-interconnect coupling models. The equivalent graph of the field-to-interconnect coupling is established. The modeling methodology consists in defining the primitive sub-network elements (vias, interconnect lines, pads, and ground plane). Kron's graph equivalent to the EMC problem is elaborated. Finally, the coupling voltages are calculated via the tensorial equation translated from the graph. The radiated EMC Kron's model is validated with a four-layer PCB from 0.4 to 1.4 GHz by two scenarios of EM radiation. As proof-of-concept, a prototype of four-layer PCB was designed, fabricated, tested, and simulated in full wave with a commercial three-dimensional EM tool. For the first case, the multilayer PCB was illuminated by plane wave emission propagating in different directions. The numerical computation from Kron's formalism was compared with simulation and measurement. The other case is the field-to-interconnect coupling between a microstrip I-line PCB, as an EM field emitter, and the multilayer PCB, as a receiver, in 1-m distance. For both cases, the simulated and calculated voltage couplings onto the multilayer PCB are in good agreement.

Thermal modelling of multilayer walls for building retrofitting applications

Abstract: Today the building sector consumes than third of global energy consumption. Thus, improving building envelope performance can optimize building thermal and energy efficiency. This paper introduces an original modelling of thermal dynamic in the building wall. The model will help us to understand the heat transfer mechanism of multilayer walls to better support building retrofits, in order to reduce energy consumption. The model is based on the Kron's method developed with the Tensorial Analysis of Networks (TAN). The feasibility of the model is studied with a multi-layer pieces of wall. The TAN thermal modelling methodology is described with different steps of routine algorithm. The Kron's graph equivalent model is elaborated from the Cauer thermal model applied to multi-layer structure. Then, the TAN equation traducing analytically the thermal problem is established. As results, the thermal flux through two- and five-layer of wall was determined. The effectiveness of the building wall TAN model was verified with numerical parameters from a residential building located in the north of the France, subject to a retrofit problem. The thermal loss, was estimated for different parameters of materials constituting the piece of wall, is given to perform the building retrofit strategies.

NGD Analysis of Turtle-Shape Microstrip Circuit

Abstract: A negative group delay (NGD) design of a turtle shape circuit topology is developed in this brief. The topology is comprised of two different length transmission lines (TLs) interconnecting two identical coupled lines (CLs). The S-matrix model is established as a function of the TL and CL parameters. The group delay (GD) at the half wave frequency of the short interconnect TL is derived from the transmission coefficient. To verify the relevance of the proposed turtle circuit theory, a microstrip proof of concept was modeled, designed, simulated, fabricated, and tested. The calculated, simulated and measured results are in good agreement and confirm the turtle prototype bandpass NGD function with approximately 1.97 GHz center frequency and NGD level of approximately −1.3 ns. In addition, this passive circuit operates with very low losses less than −2.5 dB over the reflection coefficient better than −14 dB.

Braid Shielding Effectiveness Kron’s Model via Coupled Cables Configuration

Abstract: This brief develops a circuit theory on shielding effectiveness (SE) Kron’s modelling of parallel coupled nude-braided cables. The model is established via the approach of tensorial analysis of networks (TAN). The cable structure graph is elaborated from the lumped equivalent circuit including the braided cable transfer impedance. The SE is formulated from the branch and mesh space analyses by the mean of Kron’s formalism. To verify the relevance of the SE TAN model, comparisons with commercial tools using SPICE and 3D design full wave simulations are performed. As expected, the computed SE from 150-MHz to 750-MHz with tens-centimeter lengths cable braided assumed having 95.5% optical coverage is in good agreement with simulations.

S-Parameter Model of IB-Shape Interconnect Lines Including Crosstalk Perturbation

Abstract: An innovative crosstalk effect modeling between I and B shape interconnect structure is investigated. The equivalent topology of the victim interconnect line (IL) in proximity of the B-shape line perturbation with three-coupled line (CL) is established. The IB topology S-matrix is calculated as a function of the IL and coupling coefficient parameters from the CL hexapole equivalent black box. The unfamiliar phenomenological analysis on the transmission coefficient antiresonance is associated to particular behavior of group delay. Analytical expression illustrates the relation between the particular phenomenon to the B-IL physical length and crosstalk. The theoretical investigation was confirmed with the victim I-IL transmission coefficient is influenced by the B-line crosstalk. Simulations and measurements with two IB IL microstrip prototypes validate experimentally the established three-CLs-based analytical S-parameter model.

Zonal Thermal Room Original Model With Kron’s Method

Abstract: An original thermal model of a single room structure is developed by using the tensorial network-based Kron’s method. The modelling principle is using the equivalent RC-network of wall, door and air constituting the house. For a better understanding, the temperature propagation was assumed only in a 1-D horizontal direction. The problem geometrization is defined in function of rectangular approximation meshing. After the determination of the equivalent thermal resistor and thermal capacitor, the innovative thermal circuit representing the room is elaborated. The methodology of the Kron’s formalism, implicitly described with the different action steps is introduced. The thermal room Kron’s method is implemented from the branch to mesh spaces before the expression of the problem metric. The thermal transfer functions (TTFs) at three cases of indoor points, situated near, middle and far of the door are established from the Kron’s problem metric. The feasibility of the room thermal Kron’s TTF model is validated with SPICE TTF simulations in both frequency and time domains. The thermal cut-off frequencies are verified with very good correlation between the established TTF model and simulation. An excellent prediction of transient responses with unit-step and arbitrary waveform temperature signals with a minimal and maximal amplitude of about 20°C and 40°C is proposed.

Cable Delay Cancellation with Low-Pass NGD Function

Abstract: This paper develops a cancellation method of cable delay. The proposed method is based on the low-pass negative group delay (NGD) function. The NGD circuit is constituted by a resistor and RC-parallel network mounted in L-cell and a non-inverter amplifier. The design equations of the NGD circuit are established in function of the cable delay and the operated signal bandwidth. The feasibility of the delay cancellation method is verified with simulations of network constituted by three parallel cables with 2 m, 4 m and 6 m physical lengths. Due to the low-pass NGD function, time-domain results show the cable delay cancellation effect. The cable outputs are synchronized with the pulse input signal with 0.25 µs duration.

Innovative Theory of Low-Pass NGD via-Hole-Ground Circuit

Abstract: The via ground (GND) structure constitutes one of the most useful elements for designing high performance printed circuit boards (PCBs). The electrical interconnections with vias become key regular solutions for the implementation of various electronic functions. However, so far, the vias are never being used for designing negative group delay (NGD) circuit. To answer this curious question, an original study on the design feasibility of low-pass NGD function with via ground is introduced in the present paper. After the topological description, the NGD analysis in function of the via parameters is established. The design equations allowing to synthesize the via in function of NGD function specifications are formulated. The developed NGD theory is verified with comparisons between calculations and simulations with a commercial tool. As expected, NGD value in order of hundred-picoseconds over hundred-megahertz cut-off frequencies is obtained with good agreement between the theoretical model and simulation. Furthermore, time domain analyses confirm that the via NGD structure enables to generate output signals in time-advance of arbitrary waveform input signals presenting limited bandwidth.

Reduction Technique of Differential Propagation Delay with Negative Group Delay Function

Abstract: This paper deals with an innovative technique of propagation delay reduction. The technique is based on the use of bandpass negative group delay (NGD) function. The principle of the propagation delay reduction is introduced by considering a simple scenario of Tx multi-wireless sensors communicating with a single Rx sensor. With the consideration of bandpass NGD function, it is shown that the differential between the propagation delay can be reduced considerably. The feasibility of the technique is confirmed with group delay diagram by considering microstrip NGD prototype measured S-parameters.

S-Matrix and Bandpass Negative Group Delay Innovative Theory of Ti-Geometrical Shape Microstrip Structure

Abstract: A theoretical investigation of distributed microwave circuit built with Ti-shape topology is developed. The topology under study consists of neighbored T- and i-shape interconnect lines. The Ti-topology equivalent S-matrix is calculated as a function of crosstalk coupling coefficient and coupled line (CL) delay. To highlight the NGD modelling feasibility, parametric analyses with respect to the T- and i-element coupling and delay are introduced. More practical validation is carried out with designed, simulated and measured microstrip prototype. It is found that because of T- and i-crosstalk, the Ti topology can behave as a bandpass NGD function. A good NGD performance with NGD level of approximately −1 ns around the center frequencies 2.2 GHz with transmission coefficient of approximately −2.1 dB and reflection coefficient better than −14 dB. The measured results are in good agreement with calculated models and simulations. Two-cell Ti-NGD circuits were also investigated to illustrate the designability of the topology for multi-band and widened single band NGD responses.

On the investigation of contactless bandpass NGD control with microstrip patch-based circuit

Abstract: This paper presents an investigation on innovative bandpass negative group delay (NGD) control. The bandpass NGD theory is elaborated with patch antenna-based circuit input impedance. The S-matrix ...

Cauer Ladder Inspired Kron–Branin Modeling of Thermal 1-D Diffusion

Abstract: This brief introduces an innovative unidimensional thermal propagation modeling. It consists in thermal diffusion on conductor bulk structure based on the Kron–Branin (KB) formalism. The proposed KB model is inspired from the transmission line approach by considering the bulk material thermal resistance and capacitance. The KB-based equivalent graph topology of the heated structure is elaborated. The thermal transfer function (TTF) is established from the graph analytical abstraction. The TTF enables to determine the transient and frequency-dependent temperature diffusion along the structure. The KB model effectiveness is illustrated with both frequency and time-domain analyses. Proof-of-concept constituted by copper-based bulk material is considered. The TTF from KB, finite-element-method and Cauer models are compared. With computation from dc to 100 Hz, it was shown that the frequency domain magnitude and phase are in good correction. In addition, the calculated and simulated transient heat flows along the considered structure are in good agreement by considering 120-ms duration pulse width temperature source.

Magneto-Dielectric Substrate Effect on Bandpass li-Circuit Negative Group Delay(NGD) Performance

Abstract: This paper investigates the influence of magneto-dielectric (MD) substrate permeability on the bandpass (BP) Negative Group Delay (NGD) performance. The present BP NGD analysis is based on microstrip li topology. The circuit proof of concept is designed with a coupled line (CL) having a physical 40-cm length and l-mm space. Comparison between different commercial tools is performed to illustrate the feasibility of BP NGD design with li topology. Circuit and 3-D electromagnetic (EM) full wave simulations confirm the possibility of the magneto-dielectric (MD) substrate-based BP NGD function design. The BP NGD function reveals NGD center frequency decreasing from 1.25 GHz to 1 GHz when the relative permeability, $\mu_{\mathrm{r}}$, increases from 1 to 8. In addition, the NGD value changes from about -2 to -4 ns.

Analysis of microstrip coupled line based data signal and energy hybrid receiver

Abstract: This paper develops an original circuit theory of energy and data transition. The modelling of signal and energy hybrid receiver (SEHR) is developed. The SEHR topology is described in function of t...

"Negative group delay experimentation with tee connector and cable structures", Eur. Phys. J. Appl. Phys. (EPJAP)

Abstract: The unfamiliar negative group-delay (NGD) phenomenon is experimented with structure constituted by tee-connectors and coaxial cables. The topology of the NGD generator is described. It consists of two parallel 50-Ω characteristic impedance cables. The S-parameter model in function of the cable physical lengths is established. The existence condition enabling to understand the NGD phenomenon is defined. A proof of concept simply is constituted by two three-port SMA connectors, three SMA transitions and 13-cm length cables. The NGD experimentation is performed from 1.5 GHz to 3.5 GHz. Tri-band NGD aspects in good agreement with the theory and simulation is observed experimentally. Particularly, high figure-of-merit NGD circuit with-3 ns NGD level, less than 2 dB insertion loss and 12 dB return loss around 3 GHz centre frequency is measured.-Sebastien Lallechere performed result verifications by simulation.-Blaise Ravelo was the main initiator of the NGD cable-connector structure and the development of the NGD theory.-All authors contributed on the article writing with critical reviews and corrections.

Radial stub based negative group delay circuit theory

Abstract: This study addresses a negative group delay (NGD) circuit theory regarding a distributed passive topology consisted of an open-ended radial stub. The equivalent circuit composed of the lumped R, L and C elements is proposed. Then, the S-parameter model of the passive topology is established. The NGD analysis is described from the S-parameter model. The synthesis method enabling to determine the stub parameters as a function of the targeted NGD level, frequency centre and reflection coefficient is formulated. The radial stub topology limit is explained with an analytical condition from the synthesis relation. The developed NGD theory feasibility is validated with two cases of proof-of-concept (POC). First, ideal POC circuit with NGD value varied from −2 to −1 ns around the centre frequency 1.3 GHz is confirmed with ideal optimised circuit presenting figure-of-merit of approximately −0.27. Then, the theoretical prediction is verified numerically and experimentally by designing and fabricating an actual microstrip radial stub circuit. The calculated model, simulation and measurements are in very good correlation. The prototype test results confirm that the NGD circuit exhibits an NGD of approximately −1.2 ns level at approximately 0.85 GHz centre frequency.

NGD Analysis of 10-Line Microstrip Structure Crosstalk

Abstract: An analysis of coupling effect between "1" and "0" shape lines is studied in this paper. After the "10" structure description, the two-port equivalent circuit is introduced. The S-matrix model is presented. Then, the 10-structure group delay (GD) is expressed. The theoretical equation explains that because of coupling, the 10-structure generates a bandpass NGD function around an NGD center frequency depending on the length of the 0 line. The analytical model is validated with a 10-microstrip structure. The calculated, simulated and measured results are in good correlation. The 10 prototype behaves as bandpass NGD function with 2.7 GHz center frequency, -6 ns NGD value with 6 dB insertion loss.

Negative group delay experimentation with tee connector and cable structures

Abstract: The unfamiliar negative group-delay (NGD) phenomenon is experimented with structure constituted by tee-connectors and coaxial cables. The topology of the NGD generator is described. It consists of two parallel 50-Ω characteristic impedance cables. The S-parameter model in function of the cable physical lengths is established. The existence condition enabling to understand the NGD phenomenon is defined. A proof of concept simply is constituted by two three-port SMA connectors, three SMA transitions and 13-cm length cables. The NGD experimentation is performed from 1.5 GHz to 3.5 GHz. Tri-band NGD aspects in good agreement with the theory and simulation is observed experimentally. Particularly, high figure-of-merit NGD circuit with −3 ns NGD level, less than 2 dB insertion loss and 12 dB return loss around 3 GHz centre frequency is measured.