scholarly journals Performance of Reconfigurable Antenna Fabricated on Flexible and Nonflexible Materials for Band Switching Applications

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2553
Author(s):  
B. R. Sanjeeva Reddy ◽  
Naresh K. Darimireddy ◽  
Chan-Wang Park ◽  
Abdellah Chehri
Keyword(s):  
Relative Permittivity ◽  
Ground Layer ◽  
Reconfigurable Antenna ◽  
Textile Antenna

In this article, a novel frequency slot-based switchable antenna fabricated on flexible and nonflexible materials is presented for suitable reconfigurable radiations of Bluetooth, WiMAX, and upper WLAN applications. Initially, the performance of this structure was simulated using a CSTTM simulator and evaluated experimentally using a nonflexible FR4 structure. The same antenna was implemented on a flexible (jean) substrate with a relative permittivity of 1.7. The proposed textile antenna prototypes were fabricated by optimal dimensions of an E-shaped slot with a variation on the shape of the ground layer, integrated using a crossed T-shaped strip with ON/OFF switchable state operations. The proposed antenna prototype is compact (20 × 20 mm2), providing switchable radiations with tri bands, has frequencies ranged at 2.36–2.5 GHz for Bluetooth, 3.51–3.79 GHz and 5.47–5.98 GHz for the distinct bands of WiMAX and WLAN, respectively, as well as part of UWB operations.

scholarly journals Textile-Based Antenna using Aperture-Coupled Technique for Global Positioning System (GPS) Application

2020 ◽  
Vol 5 (2) ◽  
pp. 34-42
Author(s):  
A.F.M. Pazil ◽  
◽  
N.H. Abd. Rahman ◽  
N.A. Ramli ◽  
N.F.H.A. Razak ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Relative Permittivity ◽  
Pure Copper ◽  
Design Procedure ◽  
Simulated Data ◽  
Positioning System ◽  
Textile Materials ◽  
Textile Antenna ◽  
Global Positioning ◽  
Coupled Technique

This paper presents a preliminary design of a textile antenna using aperturecoupled technique for Global Positioning System (GPS) application. Mostly used in wearable application, textile materials are suitable to be applied as the antenna substrates due to the flexibility and conformability characteristic. In this paper, felt material with the relative permittivity, εr1 of 0.76 and thickness of 2.69 mm is chosen as the substrate, and is attached to a pure copper layer as the conductive material with the thickness of 0.07 mm. Meanwhile, the textile material used as the feed substrate is fleece with the thickness of 0.69 mm with the relative permittivity εr2 of 0.91. The design procedure is discussed and the simulated data using the CST Microwave Studio software is further analysed in terms of the return loss, gain, directivity and radiation pattern.

Sensitivity of ground layer vegetation diversity descriptors in indicating forest naturalness

2006 ◽  
Vol 7 (2) ◽  
pp. 199-209 ◽  
Author(s):  
T. Standovár ◽  
P. Ódor ◽  
R. Aszalós ◽  
L. Gálhidy
Keyword(s):  
Ground Layer ◽  
Vegetation Diversity

A contribution to evaluation of influence of medium in electronic and infrared spectroscopy

1982 ◽  
Vol 47 (4) ◽  
pp. 1060-1068 ◽  
Author(s):  
Vojtěch Bekárek ◽  
Jan Juřina
Keyword(s):  
Refractive Index ◽  
Infrared Spectroscopy ◽  
Correlation Coefficient ◽  
Solvent Effects ◽  
Electronic Spectra ◽  
Relative Permittivity ◽  
Solvent Parameters

Dependence of ET(30) of solvent parameters on relative permittivity (ε) and refractive index (n) of solvent has been found for forty solvents in the form ET(30)=29.87 + 72.03 (ε - 1/(2ε + 1)-29.16(ε - 1) (n 2 - 1)/(2ε + 1) (2n2 + 1), the correlation coefficient being 0.958. Relation has been discussed between ET(30) and π solvent parameters and significance of the term (ε - 1). (n2 - 1)/(2ε + 1) (2n2 + 1) has been tested for evaluation of solvent effects in electronic spectra.>

Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

1997 ◽  
Vol 62 (10) ◽  
pp. 1533-1543
Author(s):  
Vladimír Karpenko ◽  
Jana Horálková ◽  
Milan Kodíček
Keyword(s):  
Human Serum ◽  
Systems Analysis ◽  
Titration Curve ◽  
Relative Permittivity ◽  
Structural Changes ◽  
Aliphatic Alcohol ◽  
Mixed Media ◽  
Spectrophotometric Titration ◽  
Electrostatic Effects

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

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