A leaky-wave antenna using an artificial dielectric medium

Bahl, Inder J.; Gupta, Kishan Chand

doi:10.1109/tap.1974.1140715

Cited by 67 publications

(54 citation statements)

References 6 publications

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“…The delay type materials have been extensively used for the fabrication of microwave lenses. The peculiarity of the lens is that the strip medium achieves permittivity value less than unity and hence a directional radiation pattern can be achieved [5].…”

Section: Introductionmentioning

confidence: 99%

Grating-based Dipole Antenna Configuration for High Gain Directional Radiation characteristics

Sarin¹,

Jayakrishnan

Aanandan³

et al. 2017

AEM

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The experimental and simulation studies of the radiation performance enhancement of a dipole antenna using metal strip grating are presented in this paper. The subwavelength imaging configuration of the metal strip grating is utilized for enhancing the radiation performance of the dipole antenna working in the S-band. The resultant design shows a gain of 9 dBi and a front to back ratio of -23 dB at resonance. The coupling between electric and magnetic resonances provides the necessary impedance matching performance when the antenna is brought in the vicinity of the grating.

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Section: Introductionmentioning

confidence: 99%

Grating-based Dipole Antenna Configuration for High Gain Directional Radiation characteristics

Sarin¹,

Jayakrishnan

Aanandan³

et al. 2017

AEM

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“…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%

“…Veselago predicted that a medium with simultaneous negative permittivity along with negative permeability exhibits unusual physical properties; among them are negative refraction, reversal of Doppler shift, and backward Cerenkov radiation. In the pioneering work of Pendry et al, a metallic thin wire grid was shown to exhibit a plasma frequency in the microwave regime, below which the effective permittivity takes negative values [2]. Thereafter, a splitring resonator (SRR) structure is proposed to have ( ) Ͻ 0 near the magnetic resonance frequency [3].…”

Section: Introductionmentioning

confidence: 99%

“…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. …”

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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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“…This has opened the door to various interesting wave phenomena and applications. One track in which this category of metamaterials was utilized efficiently is the field of antenna design, where ENZ or EMNZ materials were considered for tailoring the radiation patterns, that is, to attain highly directive radiation patterns [6][7][8][9][10][11][12] , or for significantly enhancing the radiation efficiency [13][14][15] . On the other hand, near-zero-parameter materials have also been extensively studied and used as means to realize unconventional tunnelling of electromagnetic energy within ultrathin subwavelength ENZ channels or bends (a phenomenon coined as supercoupling) [16][17][18][19] , tunnelling through large volumes using MNZ structures (Marcos, J.…”

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confidence: 99%

Wave–matter interactions in epsilon-and-mu-near-zero structures

2014

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In recent years, the concept of metamaterials has offered platforms for unconventional tailoring and manipulation of the light-matter interaction. Here we explore the notion of 'static optics', in which the electricity and magnetism are decoupled, while the fields are temporally dynamic. This occurs when both the relative effective permittivity and permeability attain near-zero values at a given operating frequency. We theoretically investigate some of the resulting wave features in bounded scenarios, such as unusual radiation characteristics of an emitter embedded in such epsilon-and-mu-near-zero media in bounded environments. Using such media, one might in principle 'open up' and 'stretch' the space, and have regions behaving electromagnetically as 'single points' despite being electrically large. We suggest a possible design for implementation of such structures using a single dielectric rod inserted in a waveguide operating near its cutoff frequency, providing the possibility of having electrically large 'empty' volumes to behave as epsilon-and-mu-near-zero media.

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A leaky-wave antenna using an artificial dielectric medium

Cited by 67 publications

References 6 publications

Grating-based Dipole Antenna Configuration for High Gain Directional Radiation characteristics

Grating-based Dipole Antenna Configuration for High Gain Directional Radiation characteristics

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

Wave–matter interactions in epsilon-and-mu-near-zero structures

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