Blaise Ravelo

Bio: Blaise Ravelo is an academic researcher from Nanjing University of Information Science and Technology. The author has contributed to research in topics: Group delay and phase delay & Microstrip. The author has an hindex of 21, co-authored 196 publications receiving 1727 citations. Previous affiliations of Blaise Ravelo include École Supérieure d'Ingénieurs en Génie Électrique & Nanjing University.

Novel Tee-Shaped Topology Theory of Low- and High-Pass NGD Double-Type Function

Abstract: Recent investigation reports that certain electronic circuits operate with the unfamiliar negative group delay (NGD) function. It is fundamentally stated that the NGD circuits can be classified in different types. For example, we have the simplest ones as LP and HP NGD circuit types. So far, all the NGD studies are focused on simple type function. In step up of the research about the NGD electronic circuit engineering, this paper develops an original theory of electronic circuit topology operating with double NGD-type behavior. The study consists in the theorization of three-port circuit simultaneously generating LP and HP NGD function types. The proposed three-port innovative circuit under study is innovatively composed of resistive-capacitive (RC) network of Tee-shaped topology. Moreover, the LP and HP double-NGD circuit is a first order cell which does not contain any inductive component. The LP and HP NGD analyses of the Tee-topology is based on the 3-D S-matrix modelling. Analytical investigation based on classical circuit theory is elaborated to determine the S-matrix model from the equivalent admittance matrix. The identification of the double-NGD function is established from the LP- and HP-NGD canonical forms. Hence, the specific double-NGD characteristics are defined in function of the R and C elements constituting the three-port topology. To validate the developed double-NGD theory, a proof-of-concept (PoC) of SMD lumped component-based three-port circuit is designed, simulated, fabricated and tested. The calculated, simulated and measured results from the three-port circuit PoC prototype in very good agreement confirm the double-NGD behavior. The proposed innovative NGD three-port circuit design is useful in the future for the synchronization of signals propagating through multi-way communication system.

1:4 Tree microstrip interconnect Kron-Branin model

Abstract: An uncommon computational model of printed circuit board (PCB) interconnect tree is developed. The proposed model is based on the Kron-Branin (KB) formalism. This uncommon KB method consists in traducing the tree interconnect network into a graph structure. The graph topology is constituted by the branches, nodes and coupling cords. The mathematical abstraction of the graph enables to establish the KB characteristic of the problem represented by the tree interconnect system. After the branch current calculations, the S-parameter model is established. The uncommon KB model is validated with a prototype of single-input and four-outputs (1:4) microstrip interconnect tree. As expected, the calculated S-parameters from the KB model are in good agreement with simulations and measurements from DC to 4 GHz. Thanks to the computation speed and accuracy, the KB model is prominent for the fast computation of interconnect structures and useful for the PCB EMC and signal integrity analyses.

Unity direct chain with feedback series impedance based innovative negative group delay circuit

Abstract: An innovative negative group delay (NGD) circuit theory on unity direct chain (UDC) topology is developed in this paper. The NGD UDC cells are based on the operational amplifier adder with feedback series impedance. Innovative topologies of high-pass NGD UDC cell composed of RL-series network, all-pass RC-parallel network and low-pass RC-series network are identified. It is a first time that all-pass NGD original topologies are defined. NGD analyses and synthesis methods of each NGD UDC cells are provided. The UDC cell based NGD functions are validated with SPICE simulations. The proofs-of-concept (POC) of UDCs behave as all-pass and low-pass NGD functions with group delay equal to −1 ms at very low frequencies. The low-pass NGD cut-off frequency is 424 Hz. The high pass NGD circuit generates −1 µs at the optimal NGD frequency of about 5.15 kHz. Further analysis of the operational amplifier gain and bandwidth effects is performed. The operational amplifier gain affects significantly the NGD level and bandwidth for the all considered UDC cells. Nevertheless, only the RC-parallel feedback based UDC cell is particularly sensitive to the operational bandwidth.

Analogue Behavioral Modeling of GTO

Abstract: An analog behavioral model of high power gate turn-off thyristor (GTO) is developed in this paper. The fundamental methodology for the modeling of this power electronic circuit is based on the use of the realistic diode consideration of non-linear junctions. This modeling technique enables to perform different simulations taking into account the turn-on and turn-off transient behaviors in real-time. The equivalent circuits were simulated with analog software developed in our laboratory. It was shown that the tested simple and compact model allows the generation of accurate physical characteristics of power thyristors under dynamic conditions. The model understudy was validated with analog simulations based on operational amplifier devices.

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.

Similarity and Dimensional Methods in Mechanics

Abstract: By L I Sedov London: Cleaver-Hume Press Ltd Pp xvi + 363 Price 105s This is really two separate books within the same pair of covers First of all Chapters 1-3, some 145 pages, are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics

Lectures on Theoretical Physics

Abstract: Vorlesungen uber theoretische Physik Von Prof. Arnold Sommerfeld. Band 1: Mechanik. Vierte, neubearbeitete Auflage. Pp. xii + 276. 18 D. marks. Band 2: Mechanik der deformierbaren Medien. Pp. xv + 376 + 4 plates. 18 D. marks. Band 3: Elektrodynamik. Pp. xvi + 368. 18 D. marks. Band 6: Partielle Differentialgleichungen der Physik. Pp. xiii + 332. 18 D. marks. (Wiesbaden: Dieterich'sche Verlagsbuchhandlung, 1947–1949.)

Harvesting Water Drop Energy by a Sequential Contact-Electrification and Electrostatic-Induction Process

Abstract: A new prototype triboelectric nanogenerator with superhydrophobic and self-cleaning features is invented to harvest water drop energy based on a sequential contact electrification and electrostatic induction process. Because of the easy-fabrication, cost-effectiveness, and robust properties, the developed triboelectric nanogenerator expands the potential applications to harvesting energy from household wastewater and raindrops.