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Ruann Victor de Andrade Lira

Bio: Ruann Victor de Andrade Lira is an academic researcher from Federal University of Rio Grande do Norte. The author has contributed to research in topics: Optics & Selective surface. The author has an hindex of 1, co-authored 3 publications receiving 3 citations.

Papers
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Proceedings ArticleDOI
01 Aug 2017
TL;DR: In this paper, the required parameters for the construction of microstrip antennas, which have rectangular and circular patch, were found by an optimization technique, the Taguchi Method, where each parameter is defined from the desired resonance frequency, from the electrical characteristics of the material that will be used to fabricated the antenna (thickness and dielectric constant of the substrate) and the definition of maximum and minimum values that the parameters can achieve.
Abstract: The main goal of this work is to find the required parameters for the construction of microstrip antennas, which have rectangular and circular patch. For this, an optimization technique is used, the Taguchi Method, where each parameter is defined from the desired resonance frequency, from the electrical characteristics of the material that will be used to fabricated the antenna (thickness and dielectric constant of the substrate) and the definition of maximum and minimum values that the parameters can achieve. Numerical and experimental results are presented for validation purpose of the technique.

3 citations

Journal ArticleDOI
TL;DR: In this article, bandwidth enhancement of a microstrip patch antenna using a new kind of metasurface is discussed This new geometry is used to generate new resonances in antenna and with an optimal position of the metasuran in relation to antenna, we can overlap the resonances and obtain a large bandwidth.
Abstract: In this article, bandwidth enhancement of a microstrip patch antenna using a new kind of metasurface is discussed This new geometry is used to generate new resonances in antenna and with an optimal position of the metasurface in relation to antenna we can overlap the resonances and obtain a large bandwidth The proposed antenna showed a bandwidth from 51 GHz to 80 GHz what can it able to be applied in WiFi 5 and 6 Numerical results were obtained with Ansys HFSS software A prototype was built and measurements for S11, Smith chart and gain were performed Numerical and experimental results are in good agreement

2 citations

Journal ArticleDOI
TL;DR: In this paper , a three-layered frequency-selective absorber (FSA) that can efficiently absorb electromagnetic waves (EM) in a double-band is proposed, where signals reflected from the frequency selective ground plane are located at 2.4 and 5.5 GHz (ISM and UNII bands) and absorbed by the front resistive layers.
Abstract: In this paper, a three-layered frequency-selective absorber (FSA) that can efficiently absorb electromagnetic waves (EM) in a double-band is proposed. The proposed structure is designed so that signals reflected from the frequency selective ground plane are located at 2.4 and 5.5 GHz (ISM and UNII bands) and absorbed by the front resistive layers. Simulation results show that the proposed absorber not only blocks transmission in the desired bands but absorbs the signals reflected from the conductive layer. Reflective FSS unit cells are composed of double square loops printed on an FR-4 substrate and the resistive layers are formed of OhmegaPly material with a resistivity of 50 ohms per square. Furthermore, the proposed absorber is 0.17λ thick at the lowest frequency of absorption. The experimental results agree with the numerical simulations and show an absorptivity of more than 90% at 2.4 and 5.5 GHz, covering entirely ISM and UNII bands.
Journal ArticleDOI
TL;DR: In this article , a multilayer frequency-selective absorber (FSA) for broadband operation is proposed, which consists of cascaded frequency selective surfaces, which are composed of both conductive square loops and resistive ones, which act as absorbing layer.
Abstract: Frequency Selective Surfaces (FSS) are increasingly being used in telecommunications systems due to the numerous advantages presented by this sort of structure, among them low cost, ease of fabrication, and low profile stand out. This work reports the design, fabrication, and characterization of a multilayer frequency-selective absorber (FSA) for broadband operation. The proposed structure shows an absorption performance (operating in the frequency range between 2 GHz and 6 GHz) within the transmission band. The absorber consists of cascaded frequency selective surfaces, which are composed of both conductive square loops, which reflect incident signals, and resistive ones, which act as an absorbing layer. To verify the absorbing structure performance, full-wave numerical simulations and measurements are presented. The measured results are in good agreement with the numerical ones and show that the design performs absorption above 80% within the range of 2.48 GHz to 6.13 GHz, which verifies the project properties. Besides that, numerical results show that the proposed absorber has a proper response under oblique incidence up to 30°.
Journal ArticleDOI
TL;DR: In this article, an alternative type of EBG with square holes was proposed to reduce the computational effort in simulations, which achieved suppression levels up to 6 dB in frequency selective surfaces (FSS).
Abstract: In this paper, the authors present a proposal for an application of electromagnetic bandgap (EBG), for suppression of grating lobes, in frequency selective surfaces (FSS), not yet studied in the literature. An alternative type of EBG with square holes was proposed to reduce the computational effort in simulations. The study consists of an application of a rectangular periodic array of cylindrical and square holes in FSS dielectric substrate to create rejection bands and suppress specific resonant frequency modes. We built four prototypes and compared measured results with simulated results obtained with ANSYS HFSS. Simulations and measurements show suppression levels up to 6 dB. A good agreement between the results is observed. The FSS with EBG with square holes allows a simulation time 70 % lower than FSS with EBG with cylindrical holes.

Cited by
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01 Jan 2016
TL;DR: The orthogonal arrays theory and applications is universally compatible with any devices to read and is available in the book collection an online access to it is set as public so you can get it instantly.
Abstract: Thank you for downloading orthogonal arrays theory and applications. Maybe you have knowledge that, people have search numerous times for their chosen readings like this orthogonal arrays theory and applications, but end up in malicious downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they are facing with some infectious bugs inside their desktop computer. orthogonal arrays theory and applications is available in our book collection an online access to it is set as public so you can get it instantly. Our books collection saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the orthogonal arrays theory and applications is universally compatible with any devices to read.

254 citations

Proceedings ArticleDOI
01 Jul 2018
TL;DR: The objective of this paper is to obtain the optimal parameters value of azimuth, mechanical downtilt, antenna gain and antenna height, and implement the optimized LTE radio transmitter parameters into LTE network design.
Abstract: Long Term Evolution (LTE) is newest technology for mobile telecommunication, it has some advantages that are high data rates, low Iatency and using all Internet Protocols (IP) network architecture. The implementation of LTE requires high cost and takes a long time therefore we need network planning to reduce the risks, some calculations, simulations and optimization is done in network planning. We use software named Atoll as tool for network planning and use Taguchi’s Method (TM) as optimization technique. The objective of this paper is to obtain the optimal parameters value of azimuth, mechanical downtilt, antenna gain and antenna height. The result is the responses that determine the most influential factors due to result depending on their delta value. From this paper, the most influential factor based on SN ratio is antenna height which have delta value 9.47. Then we implement the optimized LTE radio transmitter parameters into LTE network design. The result gave more 12.2% coverage area by signal level, increase average signal received power by 0.69 dBm and increase the coverage area by throughput downlink by 1.5%.

3 citations

Journal ArticleDOI
01 Nov 2022-Sensors
TL;DR: In this paper , a printed monopole antenna with stable omnidirectional radiation patterns is presented for applications in ocean buoy and the marine Internet of Things (IoT), which is composed of a rectangular patch, a cross-ground structure, and two frequency-selective surface (FSS) unit cells.
Abstract: In this paper, a printed monopole antenna with stable omnidirectional radiation patterns is presented for applications in ocean buoy and the marine Internet of Things (IoT). The antenna is composed of a rectangular patch, a cross-ground structure, and two frequency-selective surface (FSS) unit cells. The cross-ground structure is incorporated into the antenna design to maintain consistent monopole-like radiation patterns over the antenna’s operating band, and the FSS unit cells are placed at the backside of the antenna to improve the antenna gain aiming at the L-band. In addition, the FSS unit cells exhibit resonance characteristics that, when incorporated with the cross-ground structure, result in a broader impedance bandwidth compared to the conventional monopole antenna. To validate the structure, a prototype is fabricated and measured. Good agreement between the simulated and measured results show that the proposed antenna exhibits an impedance bandwidth of 83.2% from 1.65 to 4 GHz, compared to the conventional printed monopole antenna. The proposed antenna realizes a peak gain of 4.57 dBi and a total efficiency of 97% at 1.8 GHz.

3 citations

Journal ArticleDOI
01 Jan 2022
TL;DR: In this article , a multilayer antenna structure based on metasurfaces for 5G mobile applications is presented and described, which has good matching input impedance around 28 GHz, a bandwidth of 2.2 GHz and an enhancement of gain in comparison with standard patch antenna.
Abstract: This work presents and describes the design of a novel multilayer antenna structure based on metasurfaces for 5G mobile applications. The suggested antenna has good matching input impedance around 28 GHz, a bandwidth of 2.2 GHz, and an enhancement of gain in comparison with standard patch antenna. This antenna is mounted on two substrates; the first one is the foam, and the second is Roger’s substrate suitable for 5G mobile applications. The whole dimensions of the final circuit are 3.28x4.23mm 2 . The proposed antenna structure has a high gain, good matching of input impedance and an aperture angle of 57 ° which is more directive compared to the rectangular antenna element.