Active Microwave Circuit With Negative Group Delay

Ravelo, Blaise; Pérennec, André; Roy, Matthieu; Boucher, Yann

doi:10.1109/lmwc.2007.910489

Cited by 81 publications

(89 citation statements)

References 9 publications

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“…The effect of NGD is observed within a limited frequency band when the absorption or attenuation is at a maximum. Therefore, conventional approaches to realize the NGD circuits are based on bandstop structures using either series or shunt RLC resonators [4][5][6][7][8][9][10][11]. The NGD circuits have been used in various practical applications in communication systems, such as shortening or reducing delay lines [11], enhancing the efficiency of feedforward linear amplifiers [12,13], designing broadband and constant phase shifters [14], realization of non-Foster reactive elements [15], and minimizing beam-squint in series-fed antenna arrays [16].…”

Section: Introductionmentioning

confidence: 99%

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Chaudhary¹,

Jeong²

2016

PIER

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Abstract-This paper presents a comprehensive method to analyze negative group delay (NGD) phenomenon at microwave frequency. This method is based on a coupling matrix with finite unloaded quality factor resonators. Unlike conventional NGD circuit topologies that use a lumped resistor R along with bandstop resonators, the proposed topology does not require any R for generating NGD and therefore, provides fully distributed circuit realization. The proposed topology has both source to load and inter-resonator coupling structures. Analytical design equations are provided to obtain predefined NGD with matched input/output ports; the proposed structure therefore does not require any extra matching networks. From analytical analysis, it is also found that the NGD bandwidth as well as magnitude flatness can be controlled by inter-resonator couplings. The proposed design theory is proven through fabrications of NGD circuit at a center frequency of 2.14 GHz. The measurement results are in good agreement with simulations and predicted theoretical results.

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Section: Introductionmentioning

confidence: 99%

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Chaudhary¹,

Jeong²

2016

PIER

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“…5 shows the physical dimensions of the designed NGDC. These results also show that the NGD bandwidth and magnitude flatness are wider than those of NGDCs with N = 4 and N=5 and conventional NGDCs [11][12][13][14][15][16][17]. However, the trade-off among the NGD, bandwidth and magnitude flatness should be considered.…”

Section: Simulation and Experimental Resultsmentioning

confidence: 76%

“…The conventional design method of active and passive NGDCs is based on only single RLC resonators [11][12][13][14][15][16][17][18]. The NGD bandwidth and magnitude flatness should be as wide as possible for applications in RF circuits and systems.…”

Section: Introductionmentioning

confidence: 99%

Microwave Negative Group Delay Circuit: Filter Synthesis Approach

Park

Chaudhary²,

Jeong³

et al. 2016

Journal of electromagnetic engineering and science

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This paper presents the design of a negative group delay circuit (NGDC) using the filter synthesis approach. The proposed design method is based on a frequency transformation from a low-pass filter (LPF) to a bandstop filter (BSF). The predefined negative group delay (NGD) can be obtained by inserting resistors into resonators. To implement a circuit with a distributed transmission line, a circuit conversion technique is employed. Both theoretical and experimental results are provided for validating of the proposed approach. For NGD bandwidth and magnitude flatness enhancements, two second-order NGDCs with slightly different center frequencies are cascaded. In the experiment, group delay of 5.9±0.5 ns and insertion loss of 39.95±0.5 dB are obtained in the frequency range of 1.935-2.001 GHz. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

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“…As with any media exhibiting anomalous dispersion, these circuits exhibit large attenuation for any reasonable negative delay [11,12]. The attenuation can be compensated by cascading active elements with RLC resonators [9,[13][14][15]. At baseband frequencies (zero center frequency), a gain-compensated NGD effect can be achieved by cascading active elements with RC filters [16].…”

Section: Ngd Vs Out-of-band Gain Relationship In Distributed Mediamentioning

confidence: 99%

Limits of Negative Group Delay Phenomenon in Linear Causal Media

Kandic¹,

Bridges²

2013

PIER

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Abstract-Asymptotic limits of Negative Group Delay (NGD) in linear causal media satisfying Kramers-Kronig relations are investigated. Even though there is no limit on the NGD-bandwidth product of a linear medium, it is shown that the out-of-band to center frequency amplitude ratio, or out-of-band gain, increases with the NGD-bandwidth product, and is proportional to the amplitude of undesired transients when waveforms with defined "turn on/off" times propagate in the media. The optimal dispersion characteristic exhibiting NGD, which maximizes the NGD-bandwidth product as a function of the out-of-band gain, is obtained through KramersKronig relations. It is shown that the NGD-bandwidth product has an upper asymptotic limit proportional to the square root of the logarithm of the maximum out-of-band gain. The derived NGDbandwidth upper asymptotic limit of the optimally engineered causal dispersion characteristic is validated with two examples of physical media, a Lorentzian dielectric medium, and an artificially fabricated loaded transmission line medium.

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Active Microwave Circuit With Negative Group Delay

Cited by 81 publications

References 9 publications

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Microwave Negative Group Delay Circuit: Filter Synthesis Approach

Limits of Negative Group Delay Phenomenon in Linear Causal Media

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