Metamaterial-Integrated High-Gain Rectenna for RF Sensing and Energy Harvesting Applications

This paper presents a metamaterial (MTM)-integrated high-gain rectenna for RF sensing and energy harvesting applications that operates at 2.45 GHz, an industry, science, medicine (ISM) band. The novel MTM superstrate approach with a three-layered integration method is firstly introduced for rectenna applications. The integrated rectenna consists of three layers, where the first layer is an MTM superstrate consisting of four-by-four MTM unit cell arrays, the second layer a patch antenna, and the third layer a rectifier circuit. By integrating the MTM superstrate on top of the patch antenna, the gain of the antenna is enhanced, owing to its beam focusing capability of the MTM superstrate. This induces the increase of the captured RF power at the rectifier input, resulting in high-output DC power and high entire end-to-end efficiency. A parametric analysis is performed in order to optimize the near-zero property of the MTM unit cell. In addition, the effects of the number of MTM unit cells on the performance of the integrated rectenna are studied. A prototype MTM-integrated rectenna, which is designed on an RO5880 substrate, is fabricated and characterized. The measured gain of the MTM-integrated rectenna is 11.87 dB. It shows a gain improvement of 6.12 dB compared to a counterpart patch antenna without an MTM superstrate and a maximum RF–DC conversion efficiency of 78.9% at an input RF power of 9 dBm. This results in the improvement of the RF–DC efficiency from 39.2% to 78.9% and the increase of the output DC power from 0.7 mW to 6.27 mW (a factor of 8.96 improvements). The demonstrated MTM-integrated rectenna has shown outstanding performance compared to other previously reported work. We emphasize that the demonstrated MTM-integrated rectenna has a low design complexity compared with other work, as the MTM superstrate layer is integrated on top of the simple patch antenna and rectifier circuit. In addition, the number of MTM units can be determined depending on applications. It is highly envisioned that the demonstrated MTM-integrated rectenna will provide new possibilities for practical energy harvesting applications with improved antenna gain and efficiency in various IoT environments.

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Design of an Elliptical Patch Antenna for RF Energy Harvesting Application in 2.4 GHz Frequency band

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.b4937.129219 ◽

2019 ◽

Vol 9 (2) ◽

pp. 4242-4245

Keyword(s):

Energy Harvesting ◽

Frequency Band ◽

Patch Antenna ◽

Input Impedance ◽

Return Loss ◽

High Efficiency ◽

High Gain ◽

Impedance Bandwidth ◽

Basic Parameters ◽

Matched Impedance

In this paper, the design and prototype of an elliptical patch antenna is presented, which operates at the frequency of 2.4 GHz frequency band. It harvests energy from ‘Radio Frequency’ waves. The elliptical antenna has an antenna substrate made with FR4 board with dielectric constant of 3.95. The paper presents the simulation results of the basic parameters of the antenna such as: return loss, input impedance, bandwidth, gain, directivity and efficiency. The experimental results for return loss, band width and input impedance was also presented in the paper. The antenna has a gain of 5.84 dB, directivity of 6.25 dBi, return loss of -43.35 dB, bandwidth of 373 MHz, input impedance of 50.35 Ω and efficiency of 90%. The high gain, properly matched impedance for minimum return loss and high efficiency of the antenna make it eligible for energy harvesting application.

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Compact Double-Layer FR4-Based Focusing Lens Using High-Efficiency Huygens’ Metasurface Unit Cells

Sensors ◽

10.3390/s20216142 ◽

2020 ◽

Vol 20 (21) ◽

pp. 6142

Author(s):

Kd M. Raziul Islam ◽

Sangjo Choi

Keyword(s):

Double Layer ◽

Printed Circuit Board ◽

High Efficiency ◽

Transmission Loss ◽

High Gain ◽

Unit Cell ◽

Circuit Board ◽

Magnetic Current ◽

Unit Cells ◽

Focusing Lens

High transmission efficiency metasurface unit cells have been designed based on surface electric and magnetic impedances derived from Huygens’ principle. However, unit cells for low transmission loss (<1 dB) over a wide transmission phase range require at least three metallic layers, which complicates the unit cell design process. In this paper, we introduce high-efficiency Huygens’ metasurface unit cell topologies in double-layer FR4 printed circuit board (PCB) by implementing surface electric and magnetic current using the top and bottom metallic patterns and via drills. Eleven unit cells were optimized for wide phase coverage (−150° to 150°) with a low average transmission loss of −0.82 dB at 10 GHz. To demonstrate the high-efficiency of the designed unit cells, we designed and fabricated two focusing lenses with dimensions of near 150 × 150 mm (5λ × 5λ) to focus a spherical beam radiated from short focal distances (f = 100 and 60 mm). The fabricated focusing lens showed 12.87 and 13.58 dB focusing gain for f = 100 and 60 mm at 10 GHz, respectively, with a 1 dB fractional gain bandwidth of near 10%. We expect that the proposed focusing lens based on high-efficiency double-layer metasurface unit cells can help realize compact and high-gain focusing lens-integrated antenna systems.

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Bayesian removal of noise for increased sensitivity in vector pattern recognition lattice imaging of interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150800 ◽

1993 ◽

Vol 51 ◽

pp. 994-995

Author(s):

L. Fei ◽

P. Fraundorf

Keyword(s):

Pattern Recognition ◽

Perfect Crystal ◽

Unit Cell ◽

Ion Milling ◽

Beam Radiation ◽

Major Interest ◽

Unit Cells ◽

Mapping Process ◽

Increased Sensitivity ◽

Electron Microscopes

Interface structure is of major interest in microscopy. With high resolution transmission electron microscopes (TEMs) and scanning probe microscopes, it is possible to reveal structure of interfaces in unit cells, in some cases with atomic resolution. A. Ourmazd et al. proposed quantifying such observations by using vector pattern recognition to map chemical composition changes across the interface in TEM images with unit cell resolution. The sensitivity of the mapping process, however, is limited by the repeatability of unit cell images of perfect crystal, and hence by the amount of delocalized noise, e.g. due to ion milling or beam radiation damage. Bayesian removal of noise, based on statistical inference, can be used to reduce the amount of non-periodic noise in images after acquisition. The basic principle of Bayesian phase-model background subtraction, according to our previous study, is that the optimum (rms error minimizing strategy) Fourier phases of the noise can be obtained provided the amplitudes of the noise is given, while the noise amplitude can often be estimated from the image itself.

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A Wideband V-Shaped Coplanar Patch Antenna for 2-6 GHz Designed for Energy Harvesting and Wireless Communications

International Journal on Communications Antenna and Propagation (IRECAP) ◽

10.15866/irecap.v8i5.12762 ◽

2018 ◽

Vol 8 (5) ◽

pp. 406

Author(s):

Mohamed El Zoghbi ◽

Valdemar Abou Hamad ◽

Rony Ibrahim ◽

Arnaud Bréard ◽

Charbel Zgheib ◽

...

Keyword(s):

Wireless Communications ◽

Energy Harvesting ◽

Patch Antenna

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Metamaterial based Microstrip Patch Antenna Using Unit Cell Array for Gain Enhancement

International Journal of Computer Sciences and Engineering ◽

10.26438/ijcse/v7i4.285288 ◽

2019 ◽

Vol 7 (4) ◽

pp. 285-288

Author(s):

Ritu Goyal ◽

Y K Jain

Keyword(s):

Patch Antenna ◽

Microstrip Patch Antenna ◽

Unit Cell ◽

Cell Array ◽

Gain Enhancement ◽

Microstrip Patch

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Prediction of Effective Thermal Conductivities of Four-Directional Carbon/Carbon Composites by Unit Cells with Different Sizes

Applied Sciences ◽

10.3390/app11031171 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1171

Author(s):

Chang Xu ◽

Zhihong Sun ◽

Guowei Shao

Keyword(s):

Carbon Fiber ◽

Longitudinal Direction ◽

Unit Cell ◽

Carbon Composites ◽

Temperature Boundary ◽

The Matrix ◽

Unit Cells ◽

Experimental Values ◽

Different Diameters ◽

Thermal Conductivities

Two-unit cells developed to predict the effective thermal conductivities of four-directional carbon/carbon composites with the finite element method are proposed in this paper. The smaller-size unit cell is formulated from the larger-size unit cell by two 180° rotational transformations. The temperature boundary conditions corresponding to the two-unit cells are derived, and the validity is verified by the temperature and heat flux distributions at specific positions of the larger-size unit cell and the smaller-size unit cell. The thermal conductivities of the carbon fiber bundles and carbon fiber rods are measured firstly. Then, combined with the properties of the matrix, the effective thermal conductivities of the four-directional carbon/carbon composites are numerically predicted. The results in transverse direction predicted by the larger-size unit cell and the smaller-size unit cell are both higher than experimental values, which are 5.8 to 6.2% and 7.3 to 8.2%, respectively. In longitudinal direction, the calculated thermal conductivities of the larger-size unit cell and the smaller-size unit cell are 6.8% and 6.2% higher than the experimental results, respectively. In addition, carbon fiber rods with different diameters are set to clarify the influence on the effective thermal conductivities of the four-directional carbon/carbon composites.

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Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials

Materials ◽

10.3390/ma14020284 ◽

2021 ◽

Vol 14 (2) ◽

pp. 284

Author(s):

Chen Han ◽

Renbin Zhong ◽

Zekun Liang ◽

Long Yang ◽

Zheng Fang ◽

...

Keyword(s):

Energy Harvesting ◽

Fermi Level ◽

Potential Application ◽

Single Layer ◽

Wide Band ◽

Metamaterial Absorber ◽

Unit Cell ◽

Perfect Absorption ◽

Solar Energy Harvesting ◽

Band Absorption

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

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