Plasmonic Antennas for Subterranean Communications for Counter-WMD Missions

Saltenna implements plasmonics and metamaterials into innovative antenna systems which significantly increase capacity for radiofrequency (RF) signal transmissions through conductive media via efficient excitation of surface electromagnetic waves, aka “plasmons”. This novel capability may be used for improving Wi-Fi connectivity in dense urban environments and underground facilities, such as man-made tunnels and natural caves, onboard ships for boarding parties, as well as for remote examination of underground bunkers and metal enclosures (such as shipping containers, etc.). In particular, it may be used to provide practical wireless communications which will greatly outperform traditional free-space RF communications in subterranean environments during DoD missions. Traditional wireless communications links (both RF and non-RF) suffer from a number of impairments when used in subterranean spaces. While above-ground free space radio links are well understood, RF underground propagation is not. In particular, only very recently it was recognized that radio frequency surface electromagnetic waves (plasmons) may propagate underground along the boundaries of media having strongly different electric conductivity. Examples of such boundaries may include metal-soil, clay-cement and many other interfaces which are typically found in subterranean environments. Our experiments conducted during Phase 1 of this project indicate that utilization of radio frequency plasmons will considerably improve radio link performance in subterranean environments via improved plasmonic propagation through metal walls, and layers of soil and water. During Phase 2 work, we will further characterize performance of the plasmonic communication links in the presence of such underground environmental impairments as tunnel corners, walls, and doors. We will also study the impact of dust, smoke, loud noises, illuminators, and other link impairments, even though on theoretical grounds we do not expect considerable interference of such impairments with plasmonic communication links. We will continue to measure performance of plasmonic RF links based on characterization methods developed in Phase I. Development of field-proven plasmonic radios will enable DoD missions in subterranean environments, which require the real-time exchange of substantial amounts of information such as voice, video, and sensor data among personnel, sensors, and robotic systems. This is invaluable to conducting counter-WMD missions. In particular, we will demonstrate the ability of plasmonic RF communication technology to be used for remote operation of multiple robotic systems in an environment typifying an underground facility used for WMD production, storage, or use, including the first of many uses in Mapping & Awareness for Counter-WMD Operations (aka MACO), providing advanced sensing to users with a human understanding of a complex subterranean environment, determined as validated SOCOM requirements.