Because all electronics release radiation, EMI shielding is a crucial element in the design and manufacture of all military defense systems. That’s especially true for unmanned aerial vehicles (UAVs) and drones, which rely on their ability to communicate seamlessly with systems on the ground.
We’re going to take a look at why EMI shielding is so crucial in these applications, what solutions are out there for EMI protection, and how KRA has helped other clients meet EMI shielding requirements while finding those crucial extra weight savings.
Why is EMI shielding important for UAVs and drones?
In the past decade, as UAVs have played a more prominent role in military defense systems, the importance of electromagnetic shielding has also increased. That’s because these UAVs rely on communication from ground-based systems; therefore, they need to be able to transmit and receive signals from changing and unknown distances. Proper EMI shielding helps ensure the longevity of the drone or UAV, as well.
UAVs and drones are obviously complex, with many components, including radar to detect targets, RF sensors for directional support, and cameras or thermal sensors that can pick up on the heat profile of the object. All of these internal, board-level components can have cross-talk, and manufacturers need to make sure to shield against that noise. They also have to be aware of the potential for interference radiating from other devices, which can also interfere with how UAVs operate.
Shielding against both conduction, which is caused by direct contact, and radiation, which is caused by induction, helps protect components from electromagnetic interference.
Finally, there’s also the importance of ensuring the drone or UAV itself does not interfere with other devices. This is especially important within a defense context, where the failure of any device can have devastating consequences.
In addition to signal interference, EMI shielding helps prevent data breaches and hardware malfunctions, as well. Within the defense context, those are crucial precautions to take.
Electrically conductive materials, including Cho-Seal elastomer gaskets, help prevent all of this radiation from interfering with the unit, within the unit, and with other devices.
What are the most common types of gaskets?
Electrically conductive EMI gaskets are the only type of gasket that will shield UAV and other electronics from electromagnetic interference.
A few of the most commonly used types of EMI gaskets include:
- Metal BeCu spring fingers
- Mesh gaskets
- Elastomeric gaskets filled with plated metal fillers
- Electrically conductive caulks and sealants
Of course, there are other types of gaskets out there as well. Manufacturers choose the right material for each project based on a wide range of factors. Our article on EMI shielding gasket designs is a great resource on flange materials and designs for gasket junction design.
Do manufacturers really need to worry about EMI?
In a word, yes. While occasionally, manufacturers hold the mistaken belief that they don’t need to worry about shielding from EMI for their device, this is an industry standard that applies to all potential products and they will all have to be tested. It’s much more effective to design the product with EMI shielding in mind than to have to go back in and fix the issue after a failed test.
What happens if a product fails EMI testing?
It can be difficult to correct the problem if a product fails an EMI test. Engineers occasionally will try to trade the non-conductive gasket for a conductive gasket of the same size and shape, but this is not a sound strategy. Conductive gaskets have completely different design requirements than traditional gaskets, because they need to be in compression, not in shear or tension.
It’s much easier to harden your system for EMI from the get-go, ensuring gaskets are placed everywhere they may potentially be needed. If they’re not necessary for system performance and won’t cause an issue, gaskets may be able to be removed later.
Weight savings and considerations for UAVs
Weight savings are, of course, a huge consideration for manufacturers. KRA works with customers to ensure that any possible weight savings are found when selecting the correct materials and design.
For example, KRA helped one customer with a machined metal board level shield that was mated against a carbon gasket, which is less corrosion resistant. We were able to recommend switching to a conductive plastic, as well as using Ni/C to match galvanic compatibility and reduce corrosion. Additionally, we were able to mold the cover out of Premier Conductive plastic, rather than machining heavy and costly metal blocks. All told, the weight was reduced by over 50%, which is a huge savings.
In another instance, a UAV designer was using mesh to wrap and shield cables. During a visit, the customer mentioned the cable management was causing problems, not only because of the time it took to install them, but they were overweight as well. The mesh-wrapped cables were inflexible and stiff to maneuver through the intricate cabling system.
KRA immediately suggested and sampled Cho-Shrink conductive heat shrink tubing, which ended up saving over 1lb. of weight per unit. It was an overall weight reduction that also helped their unit use less power, which in turn made the unit more efficient and increased long-term field performance and reliability.
Why work with KRA to address EMI shielding?
KRA Fab is a long-time authorized distributor, fabricator, and partner to the Chomerics Division of Parker Hannifin, a world-class leader in electrically conductive material design and development.
We have expertise developing solutions for UAV and other electronic shielding needs, with a breadth of experience within the industry. We’ve helped a huge range of customers find the solutions they need for their own projects, with a focus on expert advice, carefully chosen materials, and custom guidance.