scholarly journals A Polyimide-Based Flexible Monopole Antenna Fed by a Coplanar Waveguide

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 334
Author(s):  
Dingyong Cang ◽  
Zhiliang Wang ◽  
Huiwen Qu
Keyword(s):  
Ion Exchange ◽  
Resonance Frequency ◽  
Coplanar Waveguide ◽  
Dielectric Substrate ◽  
Reduction Reaction ◽  
Monopole Antenna ◽  
Prepared Film ◽  
Relative Bandwidth ◽  
Measurement Results

A 2.4 GHz flexible monopole antenna fed by a coplanar waveguide (CPW) was presented on polyimide (PI) as the dielectric substrate, which was fabricated by in situ self-metallization. The technology does not depend on expensive equipment or complex experimental environments, including hydrolysis, ion exchange, and reduction reaction. The measurement results show that the resonance frequency of the proposed antenna is 2.28 GHz, the bandwidth is 2.06–2.74 GHz, and the relative bandwidth is 28.33% under the flat state. The bending and folding test was also carried out. Whether it was flat, bent, or folded, the measured results met the requirements of the antenna. A fatigue test was carried out to illustrate that the prepared film has high mechanical flexibility, which expands the application field of antenna.

A compact CPW-fed monopole antenna for multi-band application

2021 ◽  
pp. 1-7
Author(s):  
YunYan Zhou ◽  
NianShun Zhao ◽  
RenXia Ning ◽  
Jie Bao
Keyword(s):  
Mobile Communications ◽  
Radio Frequency Identification ◽  
Communication Systems ◽  
Satellite Communication ◽  
Coplanar Waveguide ◽  
Dielectric Substrate ◽  
Monopole Antenna ◽  
Radiation Characteristics ◽  
Frequency Bands ◽  
Compact Size

Abstract A compact coplanar waveguide-fed monopole antenna is presented in this paper. The proposed antenna is composed of three monopole branches. In order to achieve the miniaturization, the longest branch was bent. The antenna is printed on an FR4 dielectric substrate, having a compact size of 0.144λ0 × 0.105λ0 × 0.003λ0 at its lowest resonant frequency of 900 MHz. The multiband antenna covers five frequency bands: 820–990 MHz, 1.87–2.08 GHz, 2.37–2.93 GHz, 3.98–4.27 GHz, and 5.47–8.9 GHz, which covers the entire radio frequency identification bands (860–960 MHz, 2.4–2.48 GHz, and 5.725–5.875 GHz), Global System for Mobile Communications (GSM) bands (890–960 MHz and 1.850–1.990 GHz), WLAN bands (2.4–2.484 GHz and 5.725–5.825 GHz), WiMAX band (2.5–2.69 GHz), X-band satellite communication systems (7.25–7.75 GHz and 7.9–8.4 GHz), and sub 6 GHz in 5G mobile communication system (3.3–4.2 GHz and 4.4–5.0 GHz). Also, the antenna has good radiation characteristics in the operating band, which is nearly omnidirectional. Both the simulated and experimental results are presented and compared and a good agreement is established. The proposed antenna operates in five frequency bands with high gain and good radiation characteristics, which make it a suitable candidate in terminal devices with multiple communication standards.

A SIW Horn Antenna without Broad Wall Loaded with Trapezoidal Air Slot

2020 ◽  
Vol 35 (9) ◽  
pp. 1047-1052
Author(s):  
Mingxi Zhang ◽  
Wei Li ◽  
Shaobin Liu ◽  
Xiaochun Liu ◽  
Chen Wu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Surface Waves ◽  
Free Space ◽  
Impedance Matching ◽  
Horn Antenna ◽  
Dielectric Substrate ◽  
Actual Measurement ◽  
Relative Bandwidth ◽  
Measurement Results ◽  
Wide Wall

In this paper, a SIW horn antenna without broad wall loaded with trapezoidal air slot is proposed, processed, and tested. Based on the SIW horn antenna, this antenna strips off the wide wall at the horn diameter, introduces surface waves on the surface of the dielectric substrate, and improves the impedance matching between the antenna and free space. Further, trapezoidal air slots are loaded on the exposed dielectric substrate, gradually changes the dielectric constant of the dielectric substrate, so that the dielectric constant of the dielectric substrate can get closer to which of air, and the working bandwidth can be further expanded. The actual measurement results show that the working bandwidth of the antenna is 15.2-38GHz, the relative bandwidth reaches to 85.7%, and the maximum gain in the band is 9.1dBi.

scholarly journals A New Design of a CPW-Fed Dual-Band Monopole Antenna for RFID Readers

2018 ◽  
Vol 8 (2) ◽  
pp. 1040
Author(s):  
Ahmed El Hamraoui ◽  
EL Hassane Abdelmounim ◽  
Jamal Zbitou ◽  
Hamid Bennis ◽  
Mohamed Latrach
Keyword(s):  
Low Cost ◽  
Coplanar Waveguide ◽  
Monopole Antenna ◽  
Antenna Design ◽  
Dual Band ◽  
Critical Parameters ◽  
Antenna Structure ◽  
Low Profile ◽  
Measurement Results ◽  
Rfid Readers

<p>This paper comes with a new dual-band planar monopole antenna fed by Coplanar Waveguide (CPW) line designed for RFID readers and it operates at 2.45 GHz, 5.80 GHz. This antenna is designed with reasonable gain, low profile and low cost production. The designed antenna based on theoretical equations is simulated and validated by using ADS from Agilent technologies and CST Microwave Studio electromagnetic solvers. A parametric study of the proposed antenna has been carried out by optimizing some critical parameters. The antenna has a total area of 35×38 mm2 and mounted on an FR4 substrate with dielectric permittivity constant 4.4 and thickness of 1.6 mm and loss tangent 0.025. The comparison between simulation and measurement results permits to validate the final achieved antenna structure in the desired RFID frequencies bands. Details of the proposed antenna design and both simulated and experimental results are described and discussed</p>

scholarly journals NOVEL COMPACT DUAL-BROADBAND PLANAR METAMATERIAL ANTENNA

2017 ◽  
Vol 55 (3) ◽  
pp. 334
Author(s):  
Dang Nhu Dinh ◽  
Huynh Nguyen Bao Phuong ◽  
Dinh Thanh Liem ◽  
Hoang Phuong Chi ◽  
Dao Ngoc Chien
Keyword(s):  
Transmission Line ◽  
Resonance Frequency ◽  
Coplanar Waveguide ◽  
Dual Band ◽  
Frequency Bands ◽  
Left Handed ◽  
Dual Band Antenna ◽  
Metamaterial Antenna ◽  
Measurement Results

This paper proposes a novel uni-planar dual-band antenna using Composite Right Left Handed (CRLH) transmission line (CRLH-TL). Proposed antenna is designed based on the fringing effects of metamaterials and combined with coplanar waveguide (CPW) feeding in order to create two frequency bands for WLAN applications at the 2.4 and 5.5 GHz bands. Principle of gradual transform is applied to the antenna for extending the resonance frequency ranges. Optimized metamaterial antenna are fabricated and measured. Measurement results showed that the antenna operates in two broad frequency ranges spreading from 1.8 to 3.62 GHz and from 4.85 to 7.52 GHz with very compact overall dimensions of 18 mm × 16 mm (0,147 λ0 × 0.13λ0).

In-situ stabilization of silver nanoparticles in polymer hydrogels for enhanced catalytic reduction of macro and micro pollutants

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Thermo Gravimetric Analysis ◽  
Activation Parameters ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
In Situ Stabilization ◽  
Hybrid Hydrogels ◽  
Kinetics Of

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.

scholarly journals Electrokinetic and in situ spectroscopic investigations of CO electrochemical reduction on copper

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Li ◽  
Xiaoxia Chang ◽  
Haochen Zhang ◽  
Arnav S. Malkani ◽  
Mu-jeng Cheng ◽  
...  
Keyword(s):  
Mass Transport ◽  
Active Sites ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Diffusion Type ◽  
Proton Coupled Electron Transfer ◽  
Alkaline Electrolytes ◽  
Reaction Orders

AbstractRigorous electrokinetic results are key to understanding the reaction mechanisms in the electrochemical CO reduction reaction (CORR), however, most reported results are compromised by the CO mass transport limitation. In this work, we determined mass transport-free CORR kinetics by employing a gas-diffusion type electrode and identified dependence of catalyst surface speciation on the electrolyte pH using in-situ surface enhanced vibrational spectroscopies. Based on the measured Tafel slopes and reaction orders, we demonstrate that the formation rates of C2+ products are most likely limited by the dimerization of CO adsorbate. CH4 production is limited by the CO hydrogenation step via a proton coupled electron transfer and a chemical hydrogenation step of CO by adsorbed hydrogen atom in weakly (7 < pH < 11) and strongly (pH > 11) alkaline electrolytes, respectively. Further, CH4 and C2+ products are likely formed on distinct types of active sites.

Insight into the enhanced photocatalytic properties of AgBr/Ag4P2O7 composites synthesized via in situ ion exchange reaction

2021 ◽  
Vol 9 (1) ◽  
pp. 104889
Author(s):  
Wyllamanney da S. Pereira ◽  
Fabrício B. Destro ◽  
Cipriano B. Gozzo ◽  
Edson R. Leite ◽  
Júlio C. Sczancoski
Keyword(s):  
Ion Exchange ◽  
Exchange Reaction ◽  
Photocatalytic Properties ◽  
Ion Exchange Reaction ◽  
Insight Into

scholarly journals Experimental and Theoretical Studies of Sonically Prepared Cu–Y, Cu–USY and Cu–ZSM-5 Catalysts for SCR deNOx

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ultrasonic Irradiation ◽  
Active Phase ◽  
Spectroscopic Studies ◽  
In Situ Drifts ◽  
Ft Ir ◽  
Diffuse Reflectance Infrared ◽  
Experimental And Theoretical Studies

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).

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