Nonuniform Amplitude Transmitarray for Multibeam Including Near-Field Focusing

Lee, Chang‐Hyun; Lee, Jeong‐Hae

doi:10.1109/tap.2021.3098519

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…Electromagnetic (EM) metasurfaces are two-dimensional (2D) versions of metamaterials, i.e., engineered artificial materials that can realize unnatural constitutive parameters such as negative permittivity and/or permeability [ 1 , 2 , 3 ]. Based on their versatile functionalities, the metasurfaces have been adopted in many research topics such as transmissive [ 4 , 5 ] or reflective [ 6 , 7 ] antennas, cloaks [ 8 , 9 ], sensors [ 10 , 11 ], and absorbers [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. Among them, EM metasurface absorbers have attracted great attention from the perspective of a wide range of possible applications such as sensing [ 14 ], energy harvesting [ 28 ], and stealth technologies [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

Broadband Metasurface Absorber Based on an Optimal Combination of Copper Tiles and Chip Resistors

Kim

Lee

2023

Materials

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In this study, a broadband metasurface absorber composed of an optimal combination of copper tiles connected with four chip resistors is designed and experimentally verified. After fixing the locations of the chip resistors and setting their resistances to 100 Ω, the genetic algorithm (GA) is utilized to design the optimal copper tile pattern for broadband absorption. The optimal combination of the copper tiles is identified by determining the states of the square tile pairs between copper or air, depending on the one or zero states of the bit sequence created by GA, respectively. The full-wave simulation results of the optimized metasurface absorber confirmed a −10 dB reflectance bandwidth within the frequency range of 6.57 to 12.73 GHz for the normal incidence condition, with the fractional bandwidth being 63.83%. The accuracy of the metasurface absorber was verified through an experimental result that matched well with the full-wave simulated one.

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Section: Introductionmentioning

confidence: 99%

Broadband Metasurface Absorber Based on an Optimal Combination of Copper Tiles and Chip Resistors

Kim

Lee

2023

Materials

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“…However, it is found that most of the previously-reported literature only focuses on a single characteristic that is either near-field focusing or far-field radiation. As the near-field focusing and far-field radiation require significantly distinct phases of the radiating elements, the simultaneous near-field focusing and far-field radiation can be enabled by optimizing the phase distributions [6] or amplitudes [7] of radiating elements. The optimization procedure, however, is usually time-consuming and the performance of near-field focusing and far-field radiation is highly correlated to each other.…”

Section: Introductionmentioning

confidence: 99%

Enabling Simultaneous Near-Field Focusing and Far-Field Radiation Using Multiple Lenses

Mei

Pedersen

Zhang

2022

2022 International Symposium on Antennas and Propagation (ISAP)

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This paper introduces a methodology to design a scheme enabling simultaneous near-field focusing and far-field radiation by using multiple lenses. A large-size lens is designed to convert the spherical wave emanating from the feed source to a quasi-plane wave. A small-size lens is located at a parallel plane away from the large-size lens. By imposing proper phase shifts on the small-size lens, it can capture part of the electromagnetic waves from the large-size lens to achieve a focal spot in the near-field region of the small-size lens. The gain of the radiation beam and the intensity of the focal spot can be controlled by either adjusting the area ratio of, or the separation between the large-and small-size lenses. The simulations validate the effectiveness of the proposed methodology. The proposed scheme offers an alternative solution to achieve simultaneous near-field focusing and far-field radiation.

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“…In particular, when the devices that need to charge are located in both far and near field regions, the function to simultaneously steer and focus the beam is needed to the WPT system. Various studies have been researched and published in recent years [15][16][17]. WPT to various devices using the array antenna can be implemented more efficiently by considering the weights that have to be applied to the array elements [15].…”

Section: Introductionmentioning

confidence: 99%

“…WPT to various devices using the array antenna can be implemented more efficiently by considering the weights that have to be applied to the array elements [15]. In [17], the required phase of each cell of frequency selective surface (FSS) for simultaneous beam forming and focusing are calculated mathematically by the principle of superposition.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Beam Forming and Focusing Using a Checkerboard Anisotropic Surface

Park

Lee

2022

Electronics

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A novel design method of simultaneous beam forming and focusing using a checkerboard anisotropic surface is proposed and verified in this paper. The proposed multibeam control regardless of far and near regions can easily be achieved through a rearrangement of the checkerboard structure. The unit cell of the utilized anisotropic surface consists of two identical metallic structures divided by a dielectric material. When the EM wave with a circular polarization (CP) is incident on the unit cell, the maximum transmission phase variation of the unit cell is 360 degrees by half rotation of the unit cell. A microstrip patch antenna with trimmed corners is used to launch the CP wave and the distance between the microstrip patch antenna and anisotropic surface is about 2 wavelengths considering the optimized spillover and taper efficiencies. After designing each anisotropic surface for beam forming and focusing, the unit cells of the surface are rearranged in the form of a checkerboard. The feasibility of the proposed method is confirmed by full-wave simulation and measurement for anisotropic surface with a beam forming angle of 30 degrees and beam focusing point 60 mm away from center at 5.8 GHz. The forming angle and focal length are simulated and measured to be 28 degrees and about 65 mm, respectively.

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Nonuniform Amplitude Transmitarray for Multibeam Including Near-Field Focusing

Cited by 6 publications

References 16 publications

Broadband Metasurface Absorber Based on an Optimal Combination of Copper Tiles and Chip Resistors

Broadband Metasurface Absorber Based on an Optimal Combination of Copper Tiles and Chip Resistors

Enabling Simultaneous Near-Field Focusing and Far-Field Radiation Using Multiple Lenses

Simultaneous Beam Forming and Focusing Using a Checkerboard Anisotropic Surface

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