Mine detection using time domain THz spectroscopy

The use of broadband techniques in the Terahertz (THz) region, has allowed us to probe the effectiveness of far-infrared waves to assess the penetration depths required for anti-personnel mine detection. Using THz-Time Domain Spectroscopy (THz-TDS) based methods we have probed the effective penetration depth of broadband THz pulses through soil samples collected locally in Ankara, Turkey. It was found that certain frequencies within the spectral range from 0.01 to 1THz were severely attenuated by both absorption and scattering effects dependent on the geometry and size of the particles inside the soil samples. For the most extreme case, the rocky soil sample exhibited severe attenuation of the frequencies above 0.1 THz. The measurements were repeated for wetted soil samples as well. From these results we have gained insight into the boundaries imposed by soil conditions on the detection of mines buried near and far beneath the surface. We found that the effective penetration depth is strongly affected by scattering effects and the dominant scattering mechanism is explained by Mie scattering for the soil samples in consideration rather than Rayleigh scattering.


Pattern reconfigurable antenna designs insub-6 ghz band for 5g applications
Çelik, Feza Turgay; Aydın Çivi, Hatice Özlem; Alatan, Lale; Department of Aerospace Engineering (2021-2-08)
In this thesis, design,simulations,fabrication, and radiation pattern measurementsof reconfigurable antennas for sub-6GHz application of 5G protocol are presented. Modeanalysis techniquesand array theory areemployed to have anunderstanding ofthe pattern reconfigurability conceptof the designs.As a first step, adual-fed rectangular patch antenna is designed,simulated,fabricated,and then measured. Even and odd mode definitions onthe rectangular patch antennas are employed in the design pr...
Facile fabrication of Au-Ag alloy nanoparticles on filter paper: Application in SERS based swab detection and multiplexing
Khan, Ghazanfar Ali; Demirtaş, O. Özge; Bek, Alpan; Bhatti, Arshad Saleem; Ahmed, Waqqar (2022-05-01)
© 2022 Elsevier B.V.Facile fabrication of flexible substrates containing high concentration of nanoparticles (NPs) is very promising owing to their capability of swab-based surface-enhanced Raman scattering (SERS) trace detection. However, the background signal of the substrate could compromise the trace-detection capabilities. Moreover, the presence of fluorescent molecules may result in intense fluorescence background which could overshadow the Raman peaks. Herein, we demonstrate that the surfactant-free ...
Electromagnetic shielding effectiveness of galvanostatically synthesized conducting polypyrrole films in the 300-2000 MHz frequency range
Kaynak, A (1996-07-01)
Both far-field (plane wave) and near field shielding effectiveness (SE) measurements have been conducted on electrochemically synthesized conducting polypyrrole(PPy) films with wide ranging conductivity levels (10(-2) S/cm to 45 S/cm). Go-axial transmission line, TEM test cell and TE(10) waveguide techniques were employed to measure shielding effectiveness as a function of polymer conductivity, frequency and temperature. Highly doped polypyrrole films exhibited shielding levels, above 40 dB from 300 MHz to ...
Time-Domain Characterization of the Radiation Pattern of the Terahertz Photoconductive Antennas
Elmabruk, Kholoud; Demir, Kazim; Altan, Hakan; Sahin, Asaf Behzat; ÜNLÜ, MEHMET (Springer Science and Business Media LLC, 2019-06-01)
We present a novel method to characterize the radiation pattern of the terahertz photoconductive antennas in time-domain. The method uses a modified version of the terahertz time-domain spectroscopy system, where we use the basics of physical optics and the optical path compensation principle using the delay line in the system in order to detect the spatial distribution of the terahertz radiation of the photoconductive antennas in two major planes. Using this method, we investigate two terahertz photoconduc...
On event signal reconstruction in wireless sensor networks
Atakan, Baris; Akan, Oezguer B. (2007-05-18)
In Wireless Sensor Networks (WSN), the effective detection and reconstruction of the event signal is mainly based on the regulation of sampling and communication parameters used by the sensor nodes. The aim of this paper is to understand the effect of these parameters on the reconstruction performance of event signal in WSN. Theoretical analysis and results show that with proper selection of sampling and communication parameters, the event signal can be satisfactorily reconstructed at the sink. Furthermore,...
Citation Formats
H. Altan, “Mine detection using time domain THz spectroscopy,” 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48763.