Electromagnetic interference (EMI) and radiofrequency interference (RFI) refer to electromagnetically generated noise that can interfere with products’ performance and reliability. RFI is a subset of EMI that refers to radiated emissions such as those from power or communication lines.
Design engineers must strategically reduce EMI and RFI at every opportunity, especially since some sources are naturally occurring and impossible to remove from the environment.
Engineering professionals should begin by using design choices that mitigate these unwanted effects. For example, trace placement can reduce undesirable interference since a PCB’s traces carry current from drivers and receivers.
One widely established tip is to keep the distance between traces at least several times the width of individual traces. Similarly, designers should separate signal-related traces from others, including those associated with audio or video transmission.
The design-centered tools can help all parties test different possibilities to find the ones most likely to work in the real world. One such tool allows designers to ease the transition from design to manufacture by creating a digital twin of the production environment. This format-agnostic platform also enables real-time collaboration, shortening the time required for clients to approve designs.
Select appropriate internal filters and shields
Besides following design-related best practices, professionals building electronics while reducing EMI and RFI must identify opportunities to suppress and deflect them without adding too much weight to the devices. That is especially important in cases where people build electronics for aerospace and automotive applications.
The general process is identifying trouble spots after making all appropriate design-related improvements. Engineers should then proceed by applying filtering circuits on the inputs and outputs. Next, they can apply shields. These products surround at-risk components, creating a protective barrier.
The shields are typically metal or polyester, and engineers use industrial machines to form them into the desired shapes. While filters allow harmless frequencies to pass through them, shields block and redistribute EMI to mitigate their potentially dangerous effects.
A particular point is that filters only block EMI moving through physical connections such as cables. EMI transmission occurs through the air and needs no entry point. Additionally, designers will get the best results by scrutinizing how the electronic device functions and acting accordingly. One possibility is to install filters at heat sinks to control the EMI that would otherwise come through the holes that promote thermal management.
Consider electrospray technologies
An emerging EMI protection is to deposit electrospray materials onto surfaces or components. In addition to its cost-effectiveness, this solution offers customizable results because engineers can add as much as their applications require.
Although many of these efforts are in the early stages, design engineers should monitor their progress and consider how to incorporate them into their future products. One example comes from a mechanical engineering doctoral student exploring how to apply protective layers to electronics by dispensing aerosols or liquids onto them with electricity. This approach could be especially valuable to manufacturers that create increasingly small products for which traditional shielding techniques are less suitable.
The student argues that electrospray technologies for shielding can open opportunities for protecting miniaturized devices. Her technique deposits a silver layer onto the surface, minimizing the space and costs required to protect devices.
This strategy and similar efforts could also be ideal for engineers who want to safeguard delicate electronics without adding weight. Many consumers perceive lightweight, tiny devices as more innovative than heavier, larger ones. Electrospray caters to these devices while meeting modern manufacturing requirements.
Take project-specific approaches
In addition to following these tips, electronics designers must always engage with their clients throughout their work. Such engagements allow engineering professionals to understand specific needs and identify the most effective ways to achieve successful outcomes.
What worked well in one case may be less suitable for others that seem similar. However, client feedback ensures everyone is on the same page.
Ellie Gabel is a freelance writer as well as associate editor at Revolutionized.
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