Tuesday, May 4, 2021

Abstract-Line-of-sight and non-line-of-sight links for dispersive terahertz wireless networks


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Yasaman Ghasempour,  Yasith Amarasinghe, Chia-Yi Yeh, Edward Knightly,  Daniel M. Mittleman, 

An illustration showing different frequencies (represented by “colors”) emitting at different angles by a leaky waveguide excited by a broadband input signal. The plot shows the peak frequency (in GHz) that emits at each angle (in degrees). (b) Our experimental setup including a pulse source and detector, a custom-built leaky waveguide, and motorized rotation and translation stages to investigate different multipath configurations and RX orientations.


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.
This work was supported by the U.S. National Science Foundation and Army Research Lab (ARL).

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