In military and aerospace design, the performance and weight of microwave absorbers is critical to survivability. Using manipulated particles with enhanced magnetic properties, materials scientists can maximize packing density to boost performance and minimize the weight of the absorber. Learn how materials science innovations help shield the warfighter in this article.
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How reshaping tiny particles shields the warfighter
My colleague Paul Dixon recently detailed the many challenges facing design engineers who are tasked with mitigating signal interference on and preventing return energy from military and aerospace vehicles and equipment. The challenges presented by expanding frequency ranges and corrosion deserve some extra attention, though. Corrosion is an ongoing pain point for design engineers working on naval applications. And as the span of radar and communications frequencies used in the industry has grown (from frequencies as low as 100 MHz to frequencies as high as 95 GHz), standard absorbers can’t keep up. The performance of microwave absorbers in military and aerospace applications impacts everything from signal integrity to survivability. So, these are issues the industry must address.
Historically, the primary filler material used in microwave absorbers was iron. While iron fillers effectively absorbed signal, they were vulnerable to corrosion when exposed to water. Another common filler was iron silicide, which is more resistant to corrosion, but less effective than iron at signal absorption. In the face of these deficiencies, military and aerospace design engineers need filler materials that resist corrosion and work reliably at specific frequency ranges. Fortunately, new, game-changing innovations in this space offer design engineers the opportunity to deploy corrosion-resistant and more precise microwave absorbers. Here’s how:
Manipulating size and shape
By creatively processing particles (altering particle shape, adjusting annealing temperatures and times to restructure magnetic grains, etc.), materials scientists can enhance the permeability and permittivity of filler materials, thereby improving the overall performance of the absorber. This is especially important in lower-frequency applications, given the long wavelengths at these ranges. In these lower-frequency applications, materials scientists must make the most of all the space within the absorber. Otherwise, they’ll end up with a bulky, heavy absorber.
Using these manipulated particles with enhanced magnetic properties, materials scientists can maximize packing density to boost performance and minimize the weight of the absorber. And every ounce matters when it comes to military vehicles.
Further, the use of novel magnetic alloys and coatings that are inherently corrosion-resistant enables scientists to develop high-performance, rugged absorbers that work reliably amid exposure to water and harsh substances, such as jet and missile fuel.
Measure, document, model and put it all together
As we continue to create new solutions by manipulating particles, it’s important to measure and document the permeability and permittivity of these materials. At Laird R&F Products, we load particles into resins to make sheet materials and measure the intrinsic permeability and permittivity of these materials at different volume loadings. From there, we build our own material property database, which gives us the information we need to run “what-if” scenarios and design custom absorbers for different applications. This approach – heavy on measurement and documentation – equips us to help the industry tackle these multifaceted and evolving challenges.
Collectively, this materials science work contributes to an improved ability to precisely target specific frequencies with an absorber, giving military and aerospace design engineers more effective and reliable absorbers to use on jets, ships and ground vehicles. These important advances in particle research and materials science enhance the military’s warfighting capabilities.
Rick Johnson is the aerospace and defense director at Laird Performance Materials.
Laird R&F Products is a global microwave and millimeter wave EMC solution leader serving military and aerospace design teams. Follow Laird Performance Materials for more information about protecting military electronics from signal interference.