If signal and radio waves were tangible and visible, then you would not move from around your own home without tripping on one of them. That is because signals and radio waves are literally emitted by most electrical gadgets, from smartphones to radios and laptops. But what exactly keeps these signals from effectively crossing? How come you answer a phone call via your smartphone near a computer, and the signal in your phone doesn’t disrupt the wifi connection on your PC?
The disruptions we are talking about are known as EMI or Electromagnetic interference. However, you do not experience disruptions due to EMI quite often due to the utilization of effective EMI shielding that manufacturers are now utilizing on most electrical gadgets. However, these shields come in multiple varieties, but we are going to look at one crucial type. The Low-Frequency EMI shielding. What is Low-Frequency EMI shielding? How does it function? Which components are utilized to make this EMI shield? And why is it crucial to gadgets that run on low frequency?
EMI in a Nutshell
EMI or electromagnetic interference occurs when one source effectively disrupts the signal of another source. In most cases, these sources are usually in close proximity. For example, if a smartphone receives a phone call while placed next to a radio, you might hear a crackly sound turn up on the radio, and then it goes back to normal after a while. However, at this moment, the signal from the smartphone temporarily disrupted the radio’s signal causing it to act abnormally.
EMI also goes by the name RFI (radio frequency interference). And while the example above simply states a simple example EM interference on a particular scale can cause more drastic effects than just making you miss some lines from a radio presenter.
Specifically, EMI impacts the electrical circuit of a device via induction, conduction, or coupling. What that means is that EMI can either make the electrical gadget function abnormally or make it fail.
Types of Electromagnetic Interference
There are only two types of electromagnetic interference, namely:
- Narrow-band
- Broadband
Narrow-band EMI
Narrow-band electromagnetic interference typically affects mobile phones, television stations, and radios. That is because this interference tends to happen over discrete frequencies. When this interference occurs, radio signals cross, causing the device to malfunction.
Broadband Electromagnetic Interference
Broadband interference tends to occur over a wider spectrum because it occupies a massive section of the EM spectrum. Moreover, broadband electromagnetic interference is powerful and can cause immense damage to electrical gadgets compared to narrow-brand EMI.
However, this type of EMI primarily affects gadgets that have digital data links.
Simple things such as worn brushes on a gadget’s motor can effectively cause EMI. Moreover, fluorescent lights that are defective can also cause EMI.
When drivers start their cars, they cause EMI via the ignition process. Moreover, EMI can come from a jet engine igniter, defective power lines, and much more. Therefore, EMI is hard to avoid.
In each of these examples, the gadgets you are attempting to utilize might receive varying transmitted frequencies. After receiving them, the device mixes them up, then sends them over a broad spectrum.
In the EM spectrum, radio frequency interference is at the top of the list of the most common types of interference. The energy that is radiated by engines, motors, lamps, lighting, power lines, and circuits causes this particular type of interference.
You might notice electromagnetic interference at home whenever your gadget fails to function as it is supposed to function. The same case applies to when you are at work. However, in commercial environments, this interference can cause wasted productivity, loss of data, and ruined hardware.
Low-Frequency EMI
Unlike high-frequency electromagnetic interference, low-frequency electromagnetic interference is pretty challenging to restrict from hitting sensitive circuitry. Therefore, this type of interference can easily reach power frequency levels or even go lower which could cause more problems.
As the EM wave’s frequency goes down, the absorption losses and reflection decrease while the strength of the field increases. Therefore, if you are generating a design for an EMI filter meant for low-frequency electromagnetic interference mitigation, you must make the inductor’s size pretty large. Moreover, considering all the variables at play, you must consider unique EMI shielding methods specific to low-frequency EMI shielding.
Low-Frequency Electromagnetic Interference Shielding
As the name dictates, low-frequency electromagnetic shielding refers to the methods utilized to effectively block low-frequency electromagnetic signals from disrupting the circuits of electrical devices. To achieve this feat, manufacturers have to utilize enclosures that are made out of conductive components. The components that manufacturers select usually have impeccable permeability, which helps them divert the EM fields from the gadget of interest.
Low-Frequency electromagnetic shielding is pretty effective as per reducing the EM field’s strength. On average, these shields cut the EM field’s strength by about 95%. And considering the size and cost of the shield, it is without a doubt the most suitable solution to this problem.
Materials Utilized to generate EMI Shields
Typically, at lower frequencies, the strength of the magnetic and electric fields tends to be pretty high. Therefore, manufacturers must utilize highly permeable components to achieve low-frequency electromagnetic shielding. Moreover, the materials that they select mainly depend upon the following:
- EM field’s strength
- EM field’s frequency
Low-frequency, electromagnetic shielding components are primarily selected to effectively block or alter unwanted EM fields from disrupting sensitive gadgets. Typical components utilized for electromagnetic shielding are:
- Aluminum
- Copper
These are impeccable components that have low reluctance and high permeability, making them perfect for low-frequency EMI shielding.
Other components utilized for low-frequency electromagnetic shielding include:
- Steel or mu-metal
As per low-frequency EMI shield design, you can utilize online resources that give you multiple tools.
Conclusion
The production process of various EMI shields is different according to the application areas of the shield. However, all EMI shields do one particular job, block off EM fields from disrupting the electrical signal of electronic devices. However, the shield level varies according to the type of EMI the shield is trying to shield the gadget from. First, we have high-frequency EMI shields, which shield the gadget from high-frequency EMIs. Then we have the low-frequency EMIs that shield the gadget from low-frequency EMIs. We hope this article has provided you with all the answers you were looking for regarding low-frequency EMI shielding and why it is crucial to electronic gadgets.
