This paper investigates the original circuit theory on stopband (SB) negative group delay (NGD) passive topology. The basic specifications of SB-NGD function are defined by considering the voltage transfer function (VTF) of the passive circuit. An original design method and experimentation tests of SB-NGD circuit are developed. The innovative theoretical analysis is elaborated from both magnitude and GD analytical expression of the VTF model from the resonant LC-series network passive topology. The mathematical existence condition of SB-NGD aspect is analytically explored in function of R, L, and C component parameters. The formulations of the basic equations enabling the calculation of the lumped components of the SB-NGD passive circuit in function of the desired specifications as NGD cut-off frequencies, NGD value and attenuation are established. To confirm the effectiveness of the original SB-NGD circuit theory, a proof-of-concept (POC) of SB-NGD circuit board is designed, simulated, fabricated, and experimented. As expected, despite the equivalent series resistor (ESR) effect of the inductor element, the theoretical modelling, simulation and measurement results are in good agreement. The SB-NGD behavior is confirmed with lower and upper cut-off frequencies, 0.7 kHz and 1.35 kHz, respectively. Furthermore, the corresponding NGD minimal values are −33 µs and −11 µs, respectively.
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.
This paper introduces a model and design of an innovative bandpass (BP) negative group delay (NGD) distributed circuit. The passive circuit topology under study is constituted by fully distributed elements without lumped components. The NGD passive structure is implemented as a ladder shape topology composed of distributed transmission line (TL) elements. The S-matrix model is established from TL-based equivalent Z-matrix operations with respect to the ladder geometry. As a proof of concept, a two-cell ladder prototype is designed in microstrip technology, which is simulated, fabricated, and tested. The calculated and simulated measurements are in very good agreement with the validation of BP NGD behaviour. NGD value is better than −3 ns with centre frequency between 3.56 and 3.68 GHz over more than 30 MHz NGD bandwidth being observed. The circuit operates under insertion loss better than 5 dB and reflection loss better than 8 dB. This innovative BP NGD passive circuit can be useful in the RF and microwave engineering area, for example, to reduce the signal propagation delay in the upcoming and 5G telecommunication systems.
This paper develops a circuit theory on bandpass negative group delay (NGD) topology. The NGD active lumped circuit uses a low noise amplifier (LNA). An S-parameter model is formulated. Unfamiliar, NGD function analysis is introduced by analytically defining the NGD value, bandwidth, and central frequency as a function of the topology parameters. The synthesis formulas enabling the calculation of cell parameters as a function of the targeted bandpass function specifications. To validate the circuit theory, an NGD proof of concept (PoC) is designed, simulated, and tested. As expected, simulations and measurements are in good agreement. Calculated model, simulated and measured results showing NGD level of about −10 ns around the centre frequency 0.5 GHz over the bandwidth 50 MHz validate are obtained.
This paper introduces a tensorial analysis of networks (TAN) applied to a tree asymmetrical structure. To illustrate the TAN concept easily, the present investigation is applied to a three-port structure represented by a Y-tree topology. The unfamiliar method of TAN circuit modelling is elaborated from the graph topology. The fast formulation of the Y-matrix model of the structure is established from branch and mesh space TAN analyses. The TAN model is validated with commercial tool simulation and measurements from DC up to 0.5 GHz in the frequency domain and two different waveform signals in the time domain. The proof of concept circuit is implemented in microstrip technology on an FR4-epoxy dielectric substrate. Mapping sensitivity analysis with respect to the Y-tree RLC-parameters is realized by showing that local variations around initial set of R, L, and C do not equally influence reflection and transmission coefficients over the frequency bandwidth. If a similar impact is observed at the lowest frequency, maximum variations up to 250% show the importance of parameters ranking to improve both microstrip design and modelling.
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