Zoned near-zero refractive index fishnet lens antenna: Steering millimeter waves

Pacheco‐Peña, Víctor; Orazbayev, Bakhtiyar; Beaskoetxea, Unai; Beruete, Miguel; Navarro‐Cía, Miguel

doi:10.1063/1.4869436

Cited by 23 publications

(30 citation statements)

References 26 publications

(35 reference statements)

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“…Such metamaterial has been used for advanced lens design and its good performance has been confirmed in previous works [10][11][12][13][14][15][16][17]. Due to the leaky-wave mechanism present in the fishnet metamaterial, it has the potential to lower insertion loss [8,16].…”

Section: Introductionmentioning

confidence: 72%

“…The equivalent refractive index for a finite number of plates varies with the number of periods due to the inhomogeneity of the fishnet metamaterial [18][19][20]. Considering our previous experience we use four plates (plus one dielectric plate as a protection cover), since it is a good trade-off between total thickness and electromagnetic performance in terms of insertion loss [10][11][12][13][14][15][16]. Therefore, the total thickness of the structure is w = 4t m + 5t d = 1.97 mm (~0.62 k 0 ).…”

Section: à4mentioning

confidence: 99%

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Wood zone plate fishnet metalens

Orazbayev

Beruete

Navarro‐Cía

2015

EPJ Applied Metamaterials

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-Fresnel-zone plate lenses provide focusing performance while having low profile. Unfortunately, they usually display higher reflection losses than conventional dielectric lenses. Here, we demonstrate a low-profile Wood zone plate metalens based on the fishnet metamaterial working in a near-zero regime with an equivalent refractive index less than unity (n f = 0.51). The metalens is made of alternating dielectric and fishnet metamaterial concentric rings. The use of fishnet metamaterial allows reducing the reflections from the lens, while maintaining low profile, low cost and ease of manufacturing. The lens is designed to work at the W-band of the millimeter-waves range with a focal length FL = 22.8 mm (7.5 k 0 ) aiming at antenna or radar system applications. The focusing performance of the lens along with its radiation characteristics in a lens antenna configuration have been studied numerically and confirmed experimentally, showing a gain improvement of~2.5 dB with respect to a fishnet Soret metalens.

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Section: Introductionmentioning

confidence: 72%

Section: à4mentioning

confidence: 99%

Wood zone plate fishnet metalens

Orazbayev

Beruete

Navarro‐Cía

2015

EPJ Applied Metamaterials

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“…27 This concept has been commonly applied in the design of zoned dielectric lenses and it has been proposed and experimentally demonstrated at millimeter-waves in all-metallic fishnet metalenses. [28][29][30][31] The zoning technique relies on the fact that redundant phase advance of 2π of the waves traveling inside of the lens does not contribute to the focusing. Thus, the lens section causing it can be removed.…”

Section: Zoned Metalensmentioning

confidence: 99%

[INVITED] Epsilon-near-zero metalenses operating in the visible

Pacheco‐Peña

Navarro‐Cía

Beruete

2016

Optics & Laser Technology

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Several converging lenses working in the permittivity near to zero (ENZ) regime at optical frequencies are designed using an array of metaldielectric-metal plasmonic waveguides. These plasmonic waveguides show a dispersive nature that enable to mimic an effective ENZ medium when using the fast wave transverse electric (TE 1 ) mode near its cut-off wavelength. By arranging multiple plasmonic waveguides with the correct engineered dimensions, several metalenses, including graded index (GRIN) ones, and diffractive optical elements (i.e., zoned metalenses) are proposed. The metalenses are designed at  0 = 474.9nm (f = 631.67THz) with a focal length of 10.75 0 . Numerical results demonstrate that the best performance is obtained for the case of the GRIN metalens in terms of the focal position, transversal resolution and thickness, reducing its volume up to 52.3% with respect to the smooth-profiled plano-concave metalens.

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“…Furthermore, the higher side lobe level is obtained for an output angle of 18º in the experiment with a value of -4.85 dB, which is closer to the main lobe compared with the other angles. The experimental gain (defined as the ratio of the radiated power density in the direction of maximum emission and the power density radiated by an ideal lossless isotropic radiation that emits all the power fed by the source 26 ) at the working frequency (144 GHz) has a maximum of 11 dB at 0º, which is obtained comparing the ENZ-lens with a horn antenna using the comparison method 30 . Moreover, it is shown that the maximum normalized radiation power at 18º is below -3dB, which is used as a standard of the maximum scan loss allowed for a suitable beam steering.…”

mentioning

confidence: 99%

“…Nevertheless, it is in the field of lenses where they have been more intensively investigated. [15][16][17][18] Unlike other metamaterial lenses, 15,[19][20][21][22][23][24][25][26][27] narrow hollow waveguides based ENZ lenses offer reduced reflection losses due to the squeezing/tunneling/supercoupling effect-induced impedance matching with free space. 16,17 In addition, ENZ-lenses realized by all-metallic narrow hollow rectangular waveguides have several advantages in comparison with lenses made partially or wholly from dielectrics, such as resistant to hazardous conditions and higher operation power.…”

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confidence: 99%

Mechanical 144 GHz beam steering with all-metallic epsilon-near-zero lens antenna

Pacheco‐Peña

Torres

Orazbayev

et al. 2014

Applied Physics Letters

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An all-metallic steerable beam antenna composed of an ε-near-zero (ENZ) metamaterial lens is experimentally demonstrated at 144 GHz (λ 0 = 2.083 mm). The ENZ lens is realized by an array of narrow hollow rectangular waveguides working just near and above the cut-off of the TE 10 mode. The lens focal arc on the xz-plane is initially estimated analytically as well as numerically and compared with experimental results demonstrating good agreement.Next, an open-ended waveguide is placed along the lens focal arc to evaluate the ENZ-lens antenna steerability. A gain scan loss below 3 dB is achieved for angles up to 15º. 2Within the framework of metamaterials, 1,2 artificial materials with ε-near-zero (ENZ) have been increasingly studied over the past few years due to their almost infinite phase velocity property providing interesting effects such as squeezing, tunneling and supercoupling reported initially at microwaves. [3][4][5][6][7] These properties have also been demonstrated recently using metal-dielectric-metal multilayers at near infrared and visible frequencies. 8 hazardous conditions and higher operation power. Moreover, given the concave profile of an ENZlens 28 , the illumination efficiency is improved compared with common dielectric lenses and some metamaterial lenses with convex profiles whose most distant edges are poorly illuminated. 22,29 In this paper, the mechanical beam steering capabilities of an all-metallic plano-concave ENZlens antenna 16,18 are experimentally demonstrated at 144 GHz (D-band of millimeter waves). First, the radiated power is measured at seven different angles (0º, 3º, 6º, 9º, 12º, 15º, and 18º) as a function of the feeder position on the xz-plane. Owing to reciprocity, this is equivalent to raster scanning the xzplane when the ENZ-lens is illuminated obliquely from its planar interface. These results are supported with analytical calculations based on the Huygens-Fresnel principle and numerical simulations using a plane-wave under the proper oblique incidence illumination. Second, the steering capability of the proposed ENZ-lens antenna is experimentally demonstrated by measuring the radiation pattern while shifting an open-ended rectangular waveguide (WR-7) used as a feeder at the experimental foci positions obtained in the first experiment. The experimental and analytical results demonstrate a high gain of 11 dB for 0º at the operational frequency and a gain scan loss below 3 dB for steering up to 15º. 3The fabricated plano-concave ENZ-lens is shown in Fig.1 mm, with a total number of 33  144 narrow hollow waveguides along x-and y-axes, respectively. As it has been described previously metallic waveguides working near cut-off, can emulate an ENZ medium with near zero values of propagation constant and phase advance inside the medium.Therefore, as it has been mentioned previously, if one face of the lens is planar, the other one should be designed with a concave hemi-spherical profile 15,28 instead of convex in order to convert a spherical phase front into a planar pha...

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Zoned near-zero refractive index fishnet lens antenna: Steering millimeter waves

Abstract: 24/06/14 meb. Publisher version Ok to add

Cited by 23 publications

References 26 publications

Wood zone plate fishnet metalens

Wood zone plate fishnet metalens

[INVITED] Epsilon-near-zero metalenses operating in the visible

Mechanical 144 GHz beam steering with all-metallic epsilon-near-zero lens antenna

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