Periodically loaded transmission line with effective negative refractive index and negative group velocity

Siddiqui, Omar; Mojahedi, Mo; Eleftheriades, George V.

doi:10.1109/tap.2003.817556

Cited by 251 publications

(209 citation statements)

References 21 publications

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“…Clearly, it can be seen that the derivative of the phase function (phase velocity) reverses its sign when magnetic fields exceed 300 A/m, therefore implying the presence of double negative EM parameters. 35 This field-controlled behavior is also consistent with the above discussed results about the redshift-blueshift properties of the transmission coefficients ( Fig. 2(a)) and the decrease-increase trend of the effective permittivity ( Fig.…”

supporting

confidence: 91%

Microwires enabled metacomposites towards microwave applications

Luo¹,

Qin²,

Scarpa³

et al. 2016

Journal of Magnetism and Magnetic Materials

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Abstract:The work describes the microwave behavior of polymer composites containing parallel Febased and continuous/short-cut Co-based microwire arrays. A magnetic field-tunable metacomposite feature has been identified in the hybrid microwires composite containing 3 mm spaced Co-based wires and confirmed by the presence of transmission windows in the frequency band of 1 to 3.5 GHz. The magnetically tuned redshift-blueshift in the transmission window is due to the competing dynamic interactions between the different wires and the ferromagnetic resonance of the Fe-based microwires. When the Co-based inter-wire spacing is increased to 10 mm, dual-band transmission windows in the 1.5-3.5 GHz and 9-17 GHz bandwidths were observed. These transmission windows are likely induced by the ferromagnetic resonance of Fe-based wires and the long range dipolar resonance arising between Fe-Co wire couples. The hybridization of parallel Fe-based and short Co-based wires in the composites leads to a significant enhancement of the transmission window in the 1 to 6 GHz band due to the band-gap nature of the Co-based wires. The hybrid metacomposites containing microwires seem attractive in radio frequency identification application.

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supporting

confidence: 91%

Microwires enabled metacomposites towards microwave applications

Luo¹,

Qin²,

Scarpa³

et al. 2016

Journal of Magnetism and Magnetic Materials

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“…It should be pointed out that for electrically long PRI/NRI phase-shifting lines their broadband nature could be retained if the constituent NRI section is also designed to exhibit a negative group velocity, as was done in Ref. 24. In this case, not only the signs but also the slopes of the propagation constants (versus frequency) of the NRI and PRI lines compensate, thus leading to an inherently broadband response.…”

Section: Nri-tl Metamaterials Phase-shifting Linesmentioning

confidence: 98%

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

Eleftheriades¹,

Antoniades²

2007

Modern Antenna Handbook

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In the 1960s Victor Veselago systematically examined hypothetical materials having simultaneously negative permittivity and negative permeability [1]. He described a number of unusual electromagnetic phenomena associated with such media. A characteristic property of these materials is that plane waves propagating in them would have their phase velocity antiparallel to the group velocity; hence these media would support backward waves. Likewise, the vectors describing the electric field, the magnetic field, and the propagation direction would follow the left-handed rule. For this latter reason, Veselago coined the term "left-handed" to describe these hypothetical media. Moreover, he associated this kind of "left-handedness" with the notion of negative refraction and he described several unusual focusing devices (e.g., lenses) based on negative refraction. Nevertheless, it should be pointed out that the notion of negative refraction at the interface between a normal dielectric and a dielectric supporting backward waves had been described as early as the beginning of the 20th century [2,3]. It was only recently though that people devised methods of implementing these left-handed or negative refractive index (NRI) media. The first such implementation was produced at the University of California in San Diego and comprised a volumetric periodic array of straight metallic wires and split-ring resonators to synthesize negative effective permittivity and negative effective permeability, respectively, at microwave frequencies [4,5].Another way to implement artificial materials (metamaterials) that support the phenomenon of negative refraction was subsequently proposed based on the concept of loading planar transmission-line grids with reactive elements (see subsequent sections). This transmission-line (TL) approach does not rely on loosely coupled resonators to synthesize the negative permeability; rather, it depends on the electrical connections between the constituent NRI-TL unit cells to create tightly coupled resonators, thus leading to large bandwidths over which the refractive index remains negative. The explicit formulation of Modern Antenna Handbook. Edited by Constantine A. Balanis

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“…In general, the BW of NGD circuits as shown in Fig. 2, is narrow, but the NGD property is sink, as shown by Noto [8] and Siddiqui [9].…”

Section: Designing a Passive Non-foster Circuitmentioning

confidence: 99%

Novel design of a 2.1–2.9 GHz negative capacitance using a passive non-Foster circuit

Seo

2017

IEICE Electron. Express

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Non-Foster circuits (NFC), in conjunction with the effect of negative impedance, have been applied to design broadband radio frequencies (RF) due to their wideband impedance matching ability. There are many approaches to designing non-Foster circuits that use transistors with loops inside to obtain negative reactance. Hence, conventional NFC has some problems, including complex connectivity and power consumption. In this paper, we analyse other properties of NFC phase and group delay, and we realize that these properties are related to properties of negative group delay (NGD) networks. Therefore, we proposed a new design of passive nonFoster circuits, that is less complicated and does not require power.

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Periodically loaded transmission line with effective negative refractive index and negative group velocity

Cited by 251 publications

References 21 publications

Microwires enabled metacomposites towards microwave applications

Microwires enabled metacomposites towards microwave applications

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

Novel design of a 2.1–2.9 GHz negative capacitance using a passive non-Foster circuit

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