Electromagnetic and Radio frequency interference (EMI/RFI) shield design is complex and multi-faceted, combining electrical and mechanical engineering concepts. In practice, shielding is very much an iterative process in which controlling one variable impacts another, leading to even more changes in the design.
One aspect of shield design is knowing which external signals are most critical to keep from interfering with the circuits inside. This is important from the standpoint of material selection, both for the shield structure and any subsequent plating. Knowing the frequency and amplitude of critical signals and how they behave with conductive metals helps you determine the conductivity and thickness required to achieve adequate shielding effectiveness.
Electronic devices are everywhere these days – from your cell phone to your garage door opener, to the sensors on the security cameras at the grocery store. They’re controlled by internal circuit boards, which send and receive signals with instructions about what to do (i.e. display the phone’s home screen, send power to the garage door actuator, make the camera record when an object passes).
As devices have become smaller to fit inside machines, vehicles, and medical equipment, they have also become more powerful. Their microprocessors run at higher speeds, and send high-frequency signals between circuits that are very close together.
These days when it seems everything has gone digital it’s easy to forget about all the mechanical components that are critical to electronics and batteries, especially in cars and trucks. Industry leaders, governments, and citizens all want to reduce carbon emissions and rely less on fossil fuels. At the same time, semi-autonomous and “smart” vehicles are gaining popularity for safety reasons and driver convenience.
When was the last time you drove a car or used an appliance that didn’t include some kind of electronic component? Across industries, electronic devices are becoming commonplace in vehicles, medical devices, and home appliances. They’re also showing up in new places all the time from doorbells to bathroom fixtures.