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We investigate the propagation losses in terahertz (THz) non-line-of-sight (NLoS) imaging and compare the performance to the optical counterpart. NLoS imaging exploits the multiple reflections of electromagnetic waves from surrounding surfaces to reconstruct the geometry and location of hidden objects. THz and visible/infrared radiations are attractive for NLoS imaging due to the short wavelengths and practical apertures that can support this non-conventional imaging. However, the scattering mechanisms vary significantly and determine the quality of the reconstructed images. This work compares for the first time the free-space path loss and rough surface scattering losses of a simple THz and optical NLoS imaging topology. Because specular reflections are dominant in THz scattering while optical systems suffer from strong diffuse scattering, THz NLoS imaging systems can receive considerably stronger backscattered signals.
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Line-of-sight and non-line-of-sight links for dispersive terahertz wireless networks
Despite the rapidly growing interest in exploiting millimeter and terahertz waves for wireless data transfer, the role of reflected non-line-of-sight (NLOS) paths in wireless networking is one of the least explored questions. In this paper, we investigate the idea of harnessing these specular NLOS paths for communication in directional networks at frequencies above 100 GHz. We explore several illustrative transmitter architectures, namely, a conventional substrate-lens dipole antenna and a leaky-wave antenna. We investigate how these high-gain directional antennas offer both new challenges and new opportunities for exploiting NLOS paths. Our results demonstrate the sensitivity to antenna alignment, power spectrum variations, and the disparity in supported bandwidth of various line-of-sight (LOS) and reflected path configurations. We show that NLOS paths can, under certain circumstances, offer even higher data rates than the conventional LOS path. This result illustrates the unique opportunities that distinguish THz wireless systems from those that operate at lower frequencies.
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- PAR ID:
- 10594240
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- APL Photonics
- Volume:
- 6
- Issue:
- 4
- ISSN:
- 2378-0967
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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