Time-domain terahertz reflection and transmission spectroscopy of InSb

2009 ◽  
Vol 6 (12) ◽  
pp. 2849-2851 ◽  
Author(s):  
RamuÌ„nas AdomavicÌŒius ◽  
Jan Macutkevic ◽  
Rasa SuzanovicÌŒienė ◽  
Aloyzas SÌŒiusÌŒys ◽  
Arūnas Krotkus
Keyword(s):  
Time Domain ◽  
Reflection And Transmission ◽  
Transmission Spectroscopy

Analysis for Scattering of Non-homogeneous Medium by Time Domain Volume Shooting and Bouncing Rays

2021 ◽  
Vol 36 (3) ◽  
pp. 245-251
Author(s):  
Jun Li ◽  
Huaguang Bao ◽  
Dazhi Ding
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
High Efficiency ◽  
Homogeneous Medium ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transient Electromagnetic ◽  
Frequency Domain Methods ◽  
Scattered Fields

In order to evaluate scattering from hypersonic vehicles covered with the plasma efficiently, time domain volume shooting and bouncing rays (TDVSBR) is first introduced in this paper. The new method is applied to solve the transient electromagnetic scattering from complex targets, which combines with non-homogeneous dielectric and perfect electric conducting (PEC) bodies. To simplify the problem, objects are discretized into tetrahedrons with different electromagnetic parameters. Then the reflection and transmission coefficients can be obtained by using theory of electromagnetic waves propagation in lossy medium. After that, we simulate the reflection and transmission of rays in different media. At last, the scattered fields or radiation are solved by the last exiting ray from the target. Compared with frequency-domain methods, time-domain methods can obtain the wideband RCS efficiently. Several numerical results are given to demonstrate the high efficiency and accuracy of this proposed scheme.

SIGNATURE AND SIGNAL GENERATION ASPECTS OF EXPLOSIVE DETECTION USING TERAHERTZ TIME-DOMAIN SPECTROSCOPY

2008 ◽  
Vol 18 (02) ◽  
pp. 295-306 ◽  
Author(s):  
ROBERT OSIANDER ◽  
MICHAEL J. FITCH ◽  
MEGAN LEAHY-HOPPA ◽  
YAMAC DIKMELIK ◽  
JAMES B. SPICER
Keyword(s):  
Time Domain ◽  
Explosive Detection ◽  
Reflection Spectra ◽  
Terahertz Time Domain Spectroscopy ◽  
Reflection And Transmission ◽  
Time Domain Spectroscopy ◽  
Grain Sizes ◽  
Full Analysis ◽  
Characteristic Features ◽  
Absorption Features

In the last few years, a number of researchers including our collaboration have assembled databases of terahertz (THz) time-domain spectroscopy (TDS) absorption spectra from bulk explosives. While this was a necessary and important step in demonstrating the feasibility of THz TDS for explosives detection, the goal of our research is to demonstrate selectivity of THz spectra from the clutter of background spectra coming from the substrate such as soil or sand. We have investigated THz TDS reflection spectra from sand with different grain sizes as well as from metallic powders in order to distinguish between the signals reflected from the rough surfaces compared to distributed reflections at finite depths in the granular material. With marker materials such as tartaric acid, which have absorption features in the 1-2 THz range, we have investigated the reflection spectra of granular substrates with marker chemicals, and compared this to reflection and transmission spectra of solid materials prepared in polyethylene sample pellets. In principle, the same experiments can then be performed using TNT, RDX, HMX and PETN, which all have characteristic features in the 0.5-8 THz frequency range. Absolute molecular absorption coefficients can be measured as well, and we include here preliminary values for RDX. A full analysis will be reported elsewhere.

Quantitative Measurements of Amino Acids by Terahertz Time-Domain Transmission Spectroscopy

2006 ◽  
Vol 78 (15) ◽  
pp. 5424-5428 ◽  
Author(s):  
Yuko Ueno ◽  
Rakchanok Rungsawang ◽  
Isao Tomita ◽  
Katsuhiro Ajito
Keyword(s):  
Amino Acids ◽  
Time Domain ◽  
Quantitative Measurements ◽  
Transmission Spectroscopy

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.

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