Synthesis for Negative Group Delay Circuits Using Distributed and Second-Order RC Circuit Configurations

IET Circuits, Devices & Systems

Wang

et al. 2019

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.

Section: Simulated and Experimented With Validation Resultsmentioning

confidence: 99%

Section: Advantages and Disadvantages Of The Proposed Design Methodmentioning

confidence: 99%

Canonical transfer function of band‐pass NGD circuit

IET Circuits, Devices & Systems

Wang

et al. 2019

“…The frequency-dependent expression of the li-topology S-matrix elements was established from the operation of relations (11) and (12). It can be derived from the analytical operation that the li-topology reflection and transmission coefficients are written as respectively:…”

Section: Frequency-dependent Parameters Analysismentioning

confidence: 99%

“…with ω is the angular frequency variable. Therefore, theoretical synthesis methods of lumped components based NGD circuits were developed [12], [13]. The NGD concept understanding lead to tentative NGD application propositions [14]- [23] notably in the field of RF and microwave engineering.…”

Section: Introductionmentioning

confidence: 99%

Negative Group Delay Theory on Li Topology

Ravelo

et al. 2020

IEEE Access

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. INDEX TERMS Distributed circuit, li-topology, microwave theory, negative group delay (NGD), S-matrix modelling.

“…The NGD lumped passive circuits were established from the periodical NRI TLs in parallel with the deployment of metamaterial concept [18]- [20]. Synthesis methods of R, L and C component based NGD circuits were developed [21], [22]. The NGD concept understanding leads to the certain NGD application propositions [23]- [32] notably in the field of RF and microwave engineering.…”

Section: Introductionmentioning

confidence: 99%

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

Ravelo

et al. 2019

IEEE Access

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. INDEX TERMS Microwave circuit theory, IL-shape topology, distributed topology, negative group delay (NGD), coupled lines, S-matrix modeling.