Analysis of Directive Radiation From a Line Source in a Metamaterial Slab With Low Permittivity

Lovat, Giampiero; Burghignoli, Paolo; Capolino, Filippo; Jackson, David R.; Wilton, Donald R.

doi:10.1109/tap.2006.869925

Cited by 167 publications

(127 citation statements)

References 48 publications

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“…1(b)] was also provided in Ref. 5. Results showed that the halfspace configuration could also provide a narrow beam, but not a significantly enhanced power density at broadside.…”

Section: Introductionmentioning

confidence: 93%

“…where k LW ϭ ␤ Ϫ j␣ [5]. For the plasma half-space there are no leaky waves [5] and the enhanced directivity is solely due to a ray-optic effect.…”

Section: Ray-optic Vs Leaky-wave Modelsmentioning

confidence: 99%

“…For the plasma half-space there are no leaky waves [5] and the enhanced directivity is solely due to a ray-optic effect. In an effort to explore the importance of the leaky …”

Section: Ray-optic Vs Leaky-wave Modelsmentioning

confidence: 99%

“…In particular, since the early investigations of Gupta and co-workers, wire-medium slabs have been studied because of their capability to radiate narrow directive beams with simple sources [1][2][3][4][5]. It should be noted that in Ref.…”

Section: Introductionmentioning

confidence: 99%

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High directivity in low‐permittivity metamaterial slabs: Ray‐optic vs. leaky‐wave models

Lovat¹,

Burghignoli²,

Capolino³

et al. 2006

Micro & Optical Tech Letters

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High directivity in low-permittivity metamaterial slabs: Ray-optic vs. leaky-wave models between an interface and the channel axes (cf. Ref. 3). This feature is counterintuitive to the conventional optical laws but it is totally consistent with the analysis based on the isofrequencies' for the channeled waves on anisotropic lattices discussed earlier.In the conventional isotropic periodic structures, a unit cell is representative of the respective finite arrangement when the edge cells are terminated into the matched loads. However, the feature of L-C mesh to funnel power from a point source into the narrow beam leads to the question whether load impedances of the edge cells nonadjacent to the beam axis affect the channel formation and properties of the propagating waves. To explore this effect, the load impedances outside the vicinities of the source and the channel output cells were varied. A comprehensive analysis of finite BM simulated in ADS has shown that only the first three edge nodes at the channel axis contribute to the beam formation. These observations led us to the conclusion that the channels arising on the anisotropic L-C mesh are well confined and guide waves along their axes as predicted by isofrequencies. To further elucidate the mechanism of wave channeling, the lattice portions were progressively removed to retain the mesh only around the channel axis. These alterations of the mesh arrangement incurred no visible changes of the beam shape and intensity on the truncated grids. Thus, the simulation results have proved that the propagation channel formed on the L-C mesh is truly confined to a few cells at the channel axis. This property of the L-C mesh suggests that a number of independent channels with their own impedances and axis orientations could be formed on the grid. Since the channel directions vary with frequency and the unit cell parameters, the L-C mesh can act as a spatial frequency discriminator [2,6] where each individual frequency is guided into a separate dedicated channel terminated in its own matched impedance at the mesh periphery. CONCLUSIONSIt has been shown that 2D periodic meshes composed of L-C circuits collimate waves from a point source into beams. The beam directions are prescribed by the lattice symmetry and the admittance ratio (Y 2 /Y 1 ) Ͻ 0. The basic properties of the channeled waves, determined by the isofrequencies, are invariant to the physical arrangements of the unit cells as long as the ratio (Y 2 /Y 1 ) remains constant. Effect of the unit cell structure on the channeled wave propagation has been explored for the unit cell configurations composed of double series (SSM), double parallel (PPM), and mixed parallel-series (PSM) L-C circuits. Analysis of these meshes has shown that the type (forward or backward) of channeled wave can be altered in the designed frequency band by varying only capacitance in the mesh arms. These findings are of particular significance for implementation of tunable meshes used in beam steering and phase compensation applications.An...

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“…1(b)] was also provided in Ref. 5. Results showed that the halfspace configuration could also provide a narrow beam, but not a significantly enhanced power density at broadside.…”

Section: Introductionmentioning

confidence: 93%

“…where k LW ϭ ␤ Ϫ j␣ [5]. For the plasma half-space there are no leaky waves [5] and the enhanced directivity is solely due to a ray-optic effect.…”

Section: Ray-optic Vs Leaky-wave Modelsmentioning

confidence: 99%

“…For the plasma half-space there are no leaky waves [5] and the enhanced directivity is solely due to a ray-optic effect. In an effort to explore the importance of the leaky …”

Section: Ray-optic Vs Leaky-wave Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High directivity in low‐permittivity metamaterial slabs: Ray‐optic vs. leaky‐wave models

Lovat¹,

Burghignoli²,

Capolino³

et al. 2006

Micro & Optical Tech Letters

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“…For instance, a metal backed wire-medium slab excited by an electric dipole source has recently proposed as a leaky-wave antenna with enhanced broadside radiation [1]- [2]. This phenomenon was due to the Epsilon-Near-Zero (ENZ) property of the wire medium, which, in a suitable frequency range and for particular polarizations, can be characterized by an effective relative permittivity 0 < Re[ε r ] << 1.…”

Section: Introductionmentioning

confidence: 99%

Broadside radiation enhancement using a spiral resonator MNZ metamaterial substrate

Ferrer

Romeu

Gonzalez-Arbesu

et al. 2008

2008 IEEE Antennas and Propagation Society International Symposium

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The broadside power radiation enhancement has been tested for the case of a magnetic dipole in presence of an MNZ metamaterial substrate. In order to assess the theoretical estimations, a slot antenna on a ground plane has been fabricated and an AMC composed of 1 layer square spiral resonators has been used as an MNZ metamaterial slab. The radiation patterns have been measured in the anechoic chamber, achieving a gain in directivity of more than 1 dB. However, it should be taken into account that the thickness of the fabricated metamaterial slab (6 mm) is much smaller than the theoretical optimum thickness (hundreds of mm). The directivity of the antenna might be improved when increasing the number of layers of the metamaterial slab; in fact, in such a case, the leaky waves responsible of directive radiation are expected to be more significantly excited giving rise to the sought broadside power enhancement

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Leaky‐Wave Antennas

Balanis

2007

Modern Antenna Handbook

398

274

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Analysis of Directive Radiation From a Line Source in a Metamaterial Slab With Low Permittivity

Cited by 167 publications

References 48 publications

High directivity in low‐permittivity metamaterial slabs: Ray‐optic vs. leaky‐wave models

High directivity in low‐permittivity metamaterial slabs: Ray‐optic vs. leaky‐wave models

Broadside radiation enhancement using a spiral resonator MNZ metamaterial substrate

Leaky‐Wave Antennas

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