Power Absorbing Structure for Multipath Suppression in DME Applications

Veenu Tripathi and Stefano Caizzone

Peer Reviewed

Abstract:	DME (Distance Measuring Equipment) are essential navigation aids for aeronautics and fundamental for delivering distance measurement and hence positioning to aircraft. They however suffer from multipath interference, caused by objects nearby the DME antenna reflecting the signal and hence causing the signal at reception side to oscillate, due to constructive and destructive interference between the Line of Sight (LOS) and the multipath. Conventional omnidirectional DME antennas are not effective in mitigating multipath interference, while the use of directional antennas poses a strong limit on service availability. This paper proposes the use of an absorber near DME antennas to suppress multipath interference from specific directions and improve the accuracy of distance estimations. The objective is to design an absorber using metamaterial units that can provide maximum absorption in a narrow angular area while maintaining constant gain within the highest possible HPBW (Half Power Beam Width). The absorber design and optimization, as well as its placement within the test environment, are thoroughly investigated. The proposed design is validated through full scenario simulations in Ansys HFSS, considering a virtual environment with the DME antenna, metamaterial absorber, and disturbing object. The simulation results demonstrate the effectiveness of the absorber in minimizing multipath interference and provide predicted performance for real-world scenarios. By employing absorbers, the development process of DME antenna systems can be streamlined, saving time and resources, while significantly improving overall performance in complex operating conditions.
Published in:	Proceedings of the 2024 International Technical Meeting of The Institute of Navigation January 23 - 25, 2024 Hyatt Regency Long Beach Long Beach, California
Pages:	998 - 1006
Cite this article:	Tripathi, Veenu, Caizzone, Stefano, "Power Absorbing Structure for Multipath Suppression in DME Applications," Proceedings of the 2024 International Technical Meeting of The Institute of Navigation, Long Beach, California, January 2024, pp. 998-1006. https://doi.org/10.33012/2024.19553
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