Why EMC cannot be the “final step”. Design risks in defence electronics

In many companies, EMC is still seen primarily as a requirement to be met at the end of the project. This raises the question of when such an approach begins to pose a real risk in defence systems.

“Despite being something of a niche within industrial electronics, defence systems are subject to the same phenomena as commercial electronics. This also applies to electromagnetic compatibility (EMC), which is often treated as a requirement to be met at the end of a project. In reality, however, the optimal approach should assume that EMC analysis applies to every stage of product development — from design, through prototyping and quality testing, to full-scale production. Exactly as in the civilian market,” Kowalczyk explains.

He notes that this is particularly important in electronic defence systems, which are generally more complex and require greater resources. As a result, it is critical to avoid having to step back in the development process due to EMC non-compliance, as this leads to additional costs and delays. Key risks that can negatively impact product development include time pressure forcing technological compromises (such as the use of alternative, cheaper or more readily available materials or components), budget constraints, and insufficient know-how preventing full implementation of the intended functionality.

“The risk here is primarily related to failing to meet EMC requirements defined in relevant standards and by the end customer. For this reason, it is important to monitor every phase of the project from a compatibility perspective in order to detect potential errors, gaps and inconsistencies as early as possible — not only at the final stage. Limiting verification to the end of the project may result in accumulated errors that are difficult to remove, and the need to redesign the system or the PCB can increase costs to the point where the entire project becomes questionable,” he adds.

During PCB or system design, a number of often underestimated errors can lead to a loss of signal integrity.

“Experience shows that many signal integrity issues are related to improper PCB design. In other words, in most cases a properly designed board ensures that a digital signal can pass through the transmission path without distortion or errors, which is crucial in modern high-speed electronics, where signal edges are steep and rise times are very short,” the expert says.

According to Kowalczyk, it is difficult to identify a single most common mistake, as the list could include issues with polarity and footprints (e.g. reversed pinout) preventing component assembly; traces that are too thin, leading to overheating and failure; corrosion traps such as sharp angles; short circuits; problems with vias; and improper thermal management, for example insufficient vias under heat-generating components.

Asked to identify one particularly common issue, he points to improper component placement, which can lead to signal interference, mechanical conflicts and additional assembly challenges.

“Poor layout design is usually avoided through close cooperation between designers and manufacturers, involving detailed analysis of component placement and consideration of technological requirements already at the design stage,” he concludes.

We also asked whether, with increasing frequencies and system complexity, the traditional approach to EMC is becoming insufficient — and whether a shift in designers’ mindset is required.

“It seems that the main issue is that technological progress continues to push the limits in terms of frequencies and clock speeds of digital systems. As a result, signal integrity considerations are becoming increasingly important in their design. In the past, within the classical EMC approach, signal integrity was treated more as a curiosity or a specific, marginal case encountered only in certain sectors such as defence, medical or telecommunications,” Kowalczyk explains.

He believes that today, with increasingly faster processors, these two areas are beginning to merge. As a result, the traditional understanding of electromagnetic compatibility needs to be expanded to include issues related to signal integrity.

“Engineers working on PCB design should remain open to new solutions and technologies that enable them to meet increasingly demanding requirements. More and more often, it turns out that a designer’s knowledge must be interdisciplinary, extending beyond electronics into areas such as electrical engineering, mechanics, metrology and thermodynamics,” he says.

In the future, knowledge of electronics alone may no longer be sufficient for PCB design.

In practice, the consequences of these changes are most visible in military systems, where signal integrity issues quickly move beyond the design level and begin to affect the operation of entire platforms.

According to Kowalczyk, one of the key concepts in modern armed forces is network-centric warfare (C4ISR), which aims to integrate information from multiple sources to create a common operational picture.

“Such a system integrates sensors with effectors through a command and control layer and can be described as the central nervous system of modern military organisations. Each element of this system is now digital to some extent, so the issue of maintaining signal integrity arises at every level,” he explains.

It is important to note that a lack of signal integrity can manifest itself in various ways, including errors in data processing, inefficient data transmission, incorrect target identification, difficulties in generating real-time responses, reduced accuracy, failure to respond to received commands, power loss, malfunctioning subsystems, internal damage to electronic components, limited functionality, and degradation of decision-making and command capabilities.

“The problem is even more significant because military platforms must not only meet national signal integrity requirements in order to be placed on the market, but also be resilient to hostile interference, which on the modern battlefield may take the form of forced degradation of signal integrity,” Kowalczyk concludes.

Kowalczyk will return to these topics on May 7 at Evertiq Expo in Kraków, where he will present “The impact of EMC disturbances and the importance of signal integrity in defence systems”. Registration for the event is still open.