Mitigating against RFI/EMI to maintain operational effectiveness in military applications

Author : Tim Kearvell | Elastomer Product Manager | Parker Hannifin’s Chomerics Division

01 February 2022

Parker Chomerics mil/aero applications
Parker Chomerics mil/aero applications

The 21st century battlefield is evolving at an incredible pace, where extreme amounts of data are required to enable real-time decisions. As modern defence equipment becomes increasingly sophisticated & connected through the IoT, operators can control systems such as drones from thousands of miles away via a network of complex sensors & circuits.

This article was originally featured in the February 2022 issue of EPDT magazine [read the digital issue]. And sign up to receive your own copy each month.

On the ground, in the air and at sea, complex electronics that communicate vital data surround both humans and machines. So how is it possible to maintain operational readiness and secure networks when there is so much potential for system-to-system RFI/EMI interference? And how is it best to dissipate the heat that these electronic systems generate? Tim Kearvell, Elastomer Product Manager at expert in electrically & thermally conductive materials for electronics, Parker Hannifin’s Chomerics Division explains…

The IoT has a growing role in military applications, connecting ships, planes, tanks, drones, soldiers and operating bases in a cohesive network that increases situational awareness, risk assessment and response time. However, electronic systems talking to each other causes EMI (electromagnetic interference)/RFI (radio frequency interference), which needs effective management so the operating systems can work efficiently and reliably. In particular, the rapid escalation of portable electronic devices and embedded electronic systems is prompting a considerable rise in RF (radio frequency) emissions that can lead to interference, data corruption and detection.

High potential for interference

There is no doubting the growing complexity of military electronics. This evolution, in tandem with increased bandwidths and high-frequency transmissions, means the potential for interference or crosstalk also grows, where inaccurate data could lead to false mission intelligence with potentially disastrous consequences.

As a concept, the internet of things (IoT) is driven largely by the idea that AI (artificial intelligence) and cyber warfare will dominate future military battles. The IoT therefore encompasses a large range of devices that possess intelligent physical sensing, learning and actuation capabilities through virtual or cyber interfaces. These devices include sensors, robots, drones, human wearables, biometrics, armour, weapons and other smart technologies.

For military engineers, it is vital that they deal with the subject of RFI/EMI and thermal management effectively, and in good time – not at the last minute. Put simply, there must be no interference among electronic systems, nor any thermal overloading (particularly in compact applications). For all these reasons, partnering with a proven technology expert will reap rewards.

A broad range of military equipment can benefit from the latest EMI shielding and thermal management solutions. A major recommendation here is to ensure any appointed suppliers hold official accreditation in accordance with MIL-G-83528/MIL-DTL-83528, which sets out the requirements for electrically conductive silicone and electrically conductive fluorosilicone gaskets that shield against EMI and RFI.

Vulnerable systems

Many military systems are affected by EMI/RFI and thermal issues, including control/display systems, wireless communications systems, radar, power conversion systems, navigation systems, search and tracking units, gyro units, battery management systems (BMS), microwave telecommunications systems, vision systems and GPS (Global Positioning System) to list but a few.

The key to ensuring co-existence between platforms is to design-out RFI/EMI interference. Here, several potential solutions are available to ensure battle-ready and reliable military equipment. Silicone- or fluorosilicone-based conductive elastomers, for example, fully meet the requirements of MIL-DTL-83528 to provide the perfect solution for systems such as vehicle access doors, hatch caps and radar.

A further example is form-in-place gasketing. Various conductive and non-conductive silicone grades are available to offer reliable and cost-saving solutions when designing compact equipment such as control systems, communication equipment and navigation units.

Parker Chomerics EMIShielding_CableWrap
Parker Chomerics EMIShielding_CableWrap

Another solution is conductive coatings, which deliver excellent EMI shielding, anti-static protection, corrosion resistance and surface grounding, as well as superior electrical performance to protect against lightning strikes. Structural panels, flanges and plastic housings can all benefit from conductive coatings.

Those seeking effective EMI shielding can also turn to mesh and metal gaskets. These compressible, highly resilient, all-metal EMI/EMP (electromagnetic pulse) strips are typically knitted from Monel, ferrex or aluminium wire into rectangular or round cross sections. The resulting products are ideal for use as door seals and antenna gaskets, for instance.

Taking the heat

For thermal management, it is possible to maintain sensitive electronic components within their operating temperature range limits by using heat management materials that include highly conformable, thermally efficient gap fillers and gels.

Thermal gap fillers and gels are high-performance, single-component products that prove ideal for automated dispensing processes. These advanced materials improve reliability and prevent the premature failure of electronic systems, such as radar and vision control systems, as well as power converters and electronic warfare solutions.

For design engineers who require thermal insulators, these materials are available in several forms to suit applications where the highest possible thermal, dielectric and mechanical properties are required.

Supplier selection

When appointing a potential supplier for any of these products, seek out those able to deliver proven technical know-how, close customer support and comprehensive supply chain capabilities. Only this way will it be possible to meet the specific challenges of the military sector and deliver superior, reliable and cost-effective solutions.

Parker Chomerics specialises in the core competencies of materials science and process technology, which in turn provide the basis for robust and reliable product development and custom-engineered solutions for everything from complete electronic housing solutions through to fully-integrated assemblies.

Another factor that should form part of the purchase decision is to ensure the products are environmentally robust. The device or system which carries the electronic device often suffers exposure to hostile conditions in combat, and to operate efficiently must have protection from both EMI and environmental conditions, which might include wide variations in ambient temperature, shock and vibration.

Unfortunately, while military systems (like any other) are at risk of EMI/RFI from incidental sources, in war, it is often deliberate. Today, electronic warfare is a key battle component, where the threat of electronic countermeasures, such as radar jamming and deception, are increasing, as are electromagnetic pulse (EMP) attacks. All of these factors are driving the need for greater protection from EMI and RFI.

Aircraft, combat vehicles, ships, communications equipment, safety equipment, and missile systems and launchers all need shielding to function reliably, especially as the 21st century battlefield relies on huge amounts of data to maintain operational readiness and security. Modern military vehicles, for example, are dense with intelligent systems that enable soldiers and airmen to make critical decisions in an instant. With a wide choice of shielding materials available, Parker Chomerics can help ensure the complete protection of complex safety- and mission-critical electronic systems.

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