Tunable Radio Frequency Absorptive Coating/Material
Navy SBIR 2018.1 - Topic N181-087
SPAWAR - Mr. Shadi Azoum - firstname.lastname@example.org
Opens: January 8, 2018 - Closes: February 7, 2018 (8:00 PM ET)
TECHNOLOGY AREA(S): Air
Platform, Ground/Sea Vehicles
ACQUISITION PROGRAM: PMW 770
Multi-Function Mast (OE-538) ACAT III
OBJECTIVE: Develop a coating
or material that can absorb radio frequency (RF) radiation across the Very Low
Frequency (VLF) through Ultra High Frequency (UHF) band yet can be tuned to
allow a relatively narrow range of frequencies (e.g., 3-30MHz) to pass.
Demonstrate that the coating or material can be applied to a metallic surface
such as a submarine mast.
DESCRIPTION: The submarine
fleet within the U.S. Navy has been successful in a wide range of missions.
For many of these missions, success or failure depends on the submarine’s
ability to be stealthy and remain undetected by opposing forces. While
submerged, maintaining stealth is relatively easy as most electromagnetic (EM)
waves (radio, radar, visible light, etc.) experience high attenuation when
propagating through water. However, this high attenuation of EM waves also
means communications with submarines is more challenging than with other naval
platforms. The Navy employs a variety of methods to communicate with submerged
submarines, but the methods used today are generally low data rate, one-way,
and/or compromise stealth. As a result, the preferred way to conduct high
data-rate two-way communications is for the submarine to come to periscope
depth and deploy a communications mast. Unfortunately, once the mast is
deployed, it can be detected by radar. For this reason, reduction of the
mast’s Radar Cross Section (RCS) is of high importance.
PHASE I: Identify a coating
or material that exhibits the best RF absorption yet can be tuned during
manufacturing to allow any arbitrary range of frequencies to pass. Demonstrate
and quantify RF absorption and transmission performance over a range of
frequencies in a laboratory environment. Verify through simulation and
modeling that the coating/material can be manufactured so that the passband can
be varied across any frequency range in the VLF through UHF band. Simulated
results should be compared to laboratory results to demonstrate the credibility
of the model. Define the process for applying the coating/material. Develop
prototype plans for Phase II.
PHASE II: Develop and
optimize the prototype coating or material identified in Phase I. The final
coating/material should have sufficient transmission across the passband so
that communications are not degraded, yet absorption at all other frequencies
is maximized. Produce multiple samples of the optimized material, each one
tuned to a different passband. Demonstrate the tunability of the passband by
measuring the frequency response of each sample in a laboratory environment.
Confirm that the measured passband is consistent with the expected passband.
This will demonstrate that the passband of the material can be deliberately set
to the desired frequency range (i.e., “tuned”). Demonstrate the application
process on material similar to, if not identical to, the outer material on the
OE-538 mast antenna. Show that the application process is simple, safe, and
does not damage the mast. Confirm the durability of the coating/material by
exposing it to salt water, temperature extremes, humidity, etc. Qualitatively
confirm durability through visual inspection of the coating after environmental
exposure. Note any visual indications of damage (peeling, flaking, cracking,
etc.) Quantitatively confirm durability by repeating RF absorption and
PHASE III DUAL USE
APPLICATIONS: Deliver final coating or material to a Navy facility in
sufficient quantity for testing on an OE-538 antenna. Support initial
application of material to OE-538 antenna. Support Government laboratory
testing and Environmental Qualification Testing.
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KEYWORDS: RF Absorption;
Radar Cross Section; RCS; Cosite; Coating; VLF; UHF; Communications; Stealth