scholarly journals Free-Space Materials Characterization by Reflection and Transmission Measurements using Frequency-by-Frequency and Multi-Frequency Algorithms

Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 260 ◽  
Author(s):  
Fábio Gonçalves ◽  
Alfred Pinto ◽  
Renato Mesquita ◽  
Elson Silva ◽  
Adriana Brancaccio
Keyword(s):  
Time Domain ◽  
Free Space ◽  
Dielectric Materials ◽  
Weighting Factor ◽  
Reflection And Transmission ◽  
Favorable Configuration ◽  
The Time Domain ◽  
Transmission And Reflection

The knowledge of the electromagnetic constitutive properties of materials is crucial in many applications. Free-space methods are widely used for this purpose, despite their inherent practical difficulties. This paper describes an affordable free-space experimental setup for the characterization of flat samples in 1–6 GHz in a non-anechoic environment. The extracted properties are obtained from the calibrated Scattering Parameters, using a frequency-by-frequency solution or a multi-frequency reconstruction. For the first, we describe how the Time-Domain Gating can be implemented and used for filtering the signals. For the latter, a weighting factor is introduced to balance the reflection and transmission data, allowing one to have a more favorable configuration. The different role of transmission and reflection measurements on the achievable results is analyzed with regard to experimental uncertainties and different noise scenarios. Results from the two strategies are analyzed and compared. Good agreement between simulation, measurement and literature is obtained. According to the reported results for dielectric materials, there is no need of filtering the data by a Time-Domain Gating in case of the multi-frequency approach. Experimental results for Polymethylmethacrylate (PMMA) and Polytetrafluorethylene (PTFE) samples validate both the setup and the processing.

scholarly journals Models of dielectric relaxation based on completely monotone functions

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
Roberto Garrappa ◽  
Francesco Mainardi ◽  
Maione Guido
Keyword(s):  
Time Domain ◽  
Differential Operators ◽  
Dielectric Materials ◽  
Monotone Functions ◽  
Mathematical Functions ◽  
Completely Monotone Functions ◽  
Wing Model ◽  
Completely Monotone ◽  
The Time Domain

AbstractThe relaxation properties of dielectric materials are described, in the frequency domain, according to one of the several models proposed over the years: Kohlrausch-Williams-Watts, Cole-Cole, Cole-Davidson, Havriliak-Negami (with its modified version) and Excess wing model are among the most famous. Their description in the time domain involves some mathematical functions whose knowledge is of fundamental importance for a full understanding of the models. In this work, we survey the main dielectric models and we illustrate the corresponding time-domain functions. In particular, we stress the attention on the completely monotone character of the relaxation and response functions. We also provide a characterization of the models in terms of differential operators of fractional order.

Terahertz time-domain spectroscopy characterization of nitrocellulose in transmission and reflection configurations

Optik ◽  
2020 ◽  
Vol 224 ◽  
pp. 165711
Author(s):  
Noureddine Maamar ◽  
Mohamed Lazoul ◽  
Feriel Yasmine Latreche ◽  
Djalal Trache ◽  
Jean-Louis Coutaz
Keyword(s):  
Time Domain ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Transmission And Reflection

scholarly journals ROLE OF THE 3.6M DOT TO INVESTIGATE CONNECTIONS BETWEEN LONG-GRBS AND CORE-COLLAPSE SNE

2021 ◽  
Vol 53 ◽  
pp. 127-133
Author(s):  
A. Kumar ◽  
S. B. Pandey ◽  
R. Gupta ◽  
A. Aryan ◽  
A. J. Castro-Tirado ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Global Network ◽  
Core Collapse ◽  
Robotic Telescopes ◽  
The Time Domain ◽  
Time Critical ◽  
Near Future

Newly installed 3.6m DOT at Nainital (Uttarakhand) is a novel facility for the time domain astronomy. Because of the longitudinal advantage of India, it could be used to study new transients reported by a global network of robotic telescopes. Observations with the 4K × 4K CCD Imager at the axial port of the 3.6m DOT will be very helpful in the near future towards understanding the different physical aspects of time-critical events, e.g., Gamma-ray bursts (GRBs), Supernovae, Gravitational wave candidates, etc. Using the Imager with broadband filters (Bessel UBVRI and SDSS ugriz), ~6.5' × 6.5' images could be obtained to attempt various science goals in synergy with other multi-band facilities. In this study, we present an analysis of unpublished R-band data of GRB 171205A/SN 2017iuk spanning between ~12 to 105 days since burst, that observed using the 3.6m DOT with 4K × 4K CCD Imager. In the R-band light curve, a bump appears to start from ~3 days, which shows the peak at ~15 days after the burst, clearly indicates photometric evidence of association of SN with GRB 171205A.

Exploring the discrimination power of the time domain for segmentation and characterization of active lesions in serial MR data

2000 ◽  
Vol 4 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Guido Gerig ◽  
Daniel Welti ◽  
Charles R.G. Guttmann ◽  
Alan C.F. Colchester ◽  
Gábor Székely
Keyword(s):  
Time Domain ◽  
Discrimination Power ◽  
The Time Domain

Coherent electric field characterization of molecular chirality in the time domain

2012 ◽  
Vol 41 (12) ◽  
pp. 4457 ◽  
Author(s):  
Hanju Rhee ◽  
Intae Eom ◽  
Sung-Hyun Ahn ◽  
Minhaeng Cho
Keyword(s):  
Electric Field ◽  
Time Domain ◽  
Molecular Chirality ◽  
The Time Domain

scholarly journals Free-Space Characterization of the Permeability of Inhomogeneous Magneto-Dielectric Materials

2017 ◽  
Vol 65 (12) ◽  
pp. 5035-5045 ◽  
Author(s):  
Xavier Faget ◽  
Amelie Litman ◽  
Eva Dieudonne ◽  
Stefan Enoch ◽  
Nicolas Mallejac
Keyword(s):  
Free Space ◽  
Dielectric Materials ◽  
Space Characterization

scholarly journals Directive Antenna for Ultrawideband Medical Imaging Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Amin M. Abbosh
Keyword(s):  
Human Body ◽  
Time Domain ◽  
Free Space ◽  
Short Pulse ◽  
Imaging Systems ◽  
Backward Radiation ◽  
Directive Antenna ◽  
The Time Domain ◽  
Domain Performance ◽  
Peak Gain

A compact and directive ultrawideband antenna is presented in this paper. The antenna is in the form of an antipodal tapered slot with resistive layers to improve its directivity and to reduce its backward radiation. The antenna operates over the frequency band from 3.1 GHz to more than 10.6 GHz. It features a directive radiation with a peak gain which is between 4 dBi and 11 dBi in the specified band. The time domain performance of the antenna shows negligible distortion. This makes it suitable for the imaging systems which require a very short pulse for transmission/reception. The effect of the multilayer human body on the performance of the antenna is also studied. The breast model is used for this purpose. It is shown that the antenna has more than 90% fidelity factor when it works in free space, whereas the fidelity factor decreases as the signal propagates inside the human body. However, even inside the human body, the fidelity factor is still larger than 70% revealing the possibility of using the proposed antenna in biomedical imaging systems.

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