Study and Application of Microwave Active Circuits with Negative Group Delay

Ravelo, Blaise; Pérennec, André; Roy, Matthieu

doi:10.5772/9012

Cited by 9 publications

(6 citation statements)

References 31 publications

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“…They have been used in various telecommunication applications, such as shortening of delay lines in feed-forward amplifiers [7], beam-squint minimization in phased array antennas [11], broadband balun circuits [12], [13], broadband constant phase shifters [13], [14], channel equalizers [15], and interconnect RC-delay and RLC-delay equalization [16].…”

Section: Introductionmentioning

confidence: 99%

Asymptotic Limits of Negative Group Delay in Active Resonator-Based Distributed Circuits

Kandic

Bridges

2011

IEEE Trans. Circuits Syst. I

116

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In this paper the asymptotic limits of negative group delay (NGD) phenomena in multi-stage RLC resonator-based circuits are discussed. A NGD-bandwidth-product limit is derived as a function of the number of stages and the out-of-band gain, which is independent of the circuit topology and can include active gain compensation. The limit is verified experimentally at microwave frequencies using a gain-compensated NGD circuit employing a parallel RLC resonator in the feedback path of a high-frequency op-amp. It is shown that, in the asymptotic limit, the NGD-bandwidth-product is proportional to the square root of the number of stages, and also to the square root of the logarithm of the out-ofband gain. The relation between the time-domain transient amplitude and the out-of-band gain is analyzed for finite-duration modulated signals, indicating an exponential increase in transient amplitudes with the square of NGD. Analysis shows that any attempt to increase the NGD of a finite-duration modulating waveform, by cascading more stages, is thwarted by the transients.

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Section: Introductionmentioning

confidence: 99%

Asymptotic Limits of Negative Group Delay in Active Resonator-Based Distributed Circuits

Kandic

Bridges

2011

IEEE Trans. Circuits Syst. I

116

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“…Meanwhile, well-synchronized signals are required to maintain the system coherences. In order to enhance this signal synchronization in the digital, RF/microwave and millimeter-wave equipments, various transmission data group delay enhancement techniques based on the application of negative group delay (NGD) concept in baseband and microwave bands were proposed [17][18][19][20][21][22][23][24][25][26][27]. For that, different types of electronic circuit topologies mostly, inspired from the metamaterials, were deployed to realize the NGD function.…”

Section: Introductionmentioning

confidence: 99%

An FET-based microwave active circuit with dual-band negative group delay

Ravelo

Blasi²

2011

J. Microw. Optoelectron. Electromagn. Appl.

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Recent studies proved that certain electronic active circuits are capable to exhibit simultaneously a negative group delay (NGD) and amplification in microwave frequency bands. One of the simplest topologies generating this counterintuitive NGD function effect is formed by a series RLC-network in cascade with a transistor. By using this cell, similar to the classical electronic functions, dual-band NGD microwave devices with loss compensation possibility can be designed. Theoretic demonstrations concerning the theory of the NGD circuit considered are presented. The dual-band NGD concept feasibility is concretely illustrated by an example of EM/circuit co-simulations. So, in frequency domain, dual-band NGD with minimal values of about-1 ns was observed simultaneously within two frequency bands centered at about 1.05 GHz and 2.05 GHz. To highlight the functioning of the hybrid device considered, time-domain analysis showing the RF/microwave signal advancement is performed. As application, the concept investigated can be envisaged for data synchronization in multi-channel wireless communication systems eventually degraded by undesired EMI effects.

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“…It is based on the use of an active cell composed of an FET in cascaded with shunt RLC resonant network. As introduced in [37][38][39][40], this cell generates a group delay always negative at its resonance frequency. In addition, as demonstrated in this paper that through analytical studies, because of its insertion gain form, this circuit is also susceptible to compress pulse RF signals.…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, these NGD passive structures are not suitable for microwave applications because of the narrow bandwidth and excessive losses systematically associated to the generation of significant NGD. Till 2005, the existing NGD devices were limited in either operating To overcome such problems, a simple topology of NGD active cell depicted in Figure 1 has been proposed and developed [37][38][39][40]. This structure is composed by a field effect transistor (FET) in cascade with shunt RLC series network.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Microwave Pulse Signal Compression With NGD Circuit

Ravelo¹

2011

PIER C

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This paper demonstrates the exhibition of pulse compression from an electronic circuit with negative group delay (NGD). This circuit consists of a field effect transistor (FET) cascaded with shunt RLC network. Theoretic and experimental investigations have proved that, at its resonance frequency, the group delay of this circuit is always negative. The present study shows that around this resonance, it presents a gain form enabling to generate pulse compression. To validate this concept, as proof-of-principle, devices with one-and twostages FET were implemented and tested. Measurements of the onestage test device evidenced an NGD of about −2.5 ns and simultaneously with 2 dB amplification operating at 622 MHz resonance frequency. In the frequency domain, in the case of a Gaussian input pulse with 40 MHz frequency standard deviation, this resulted in 125% expansion of pulse width compared to the input one. In time domain, simulations showed that the compression was about 80% in the case of an input Gaussian pulse with 4 ns standard deviation. With the other prototype comprised of two-stage NGD cell, the use of a sine carrier of about 1.03 GHz allowed to achieve 87% pulse width compression.

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Study and Application of Microwave Active Circuits with Negative Group Delay

Cited by 9 publications

References 31 publications

Asymptotic Limits of Negative Group Delay in Active Resonator-Based Distributed Circuits

Asymptotic Limits of Negative Group Delay in Active Resonator-Based Distributed Circuits

An FET-based microwave active circuit with dual-band negative group delay

Investigation on the Microwave Pulse Signal Compression With NGD Circuit

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