What is EMC Shielding and Why it is Important?

Avoid risks with signal interference

The development of wireless technology has increased the risk of signal interference. Any electronic device can catch unwanted signals that can interrupt the working of circuits. That’s why companies do Electromagnetic Compatibility (EMC) shielding to avoid these problems. In this article, we will shed light on EMC shielding and cover up the basic concepts you should know about.

EMC Shielding – A Brief Overview

Electromagnetic Compatibility (EMC) shielding is an approach taken to ensure the protection of the sensor signals from external electromagnetic signals. It also prevents the signals to leak out and interfere with other electronic devices. If an electronic component does not have shielding, it can cause several issues, such as interrupted communication or a completely down system. EMC shielding covers many domains including military, health, and other emergency services.

Nowadays, EMC has become an important part of electronic items. Industrialists also introduced different standards to explain whether the item is up to the mark. They perform EMC testing to know where the component is standing right now. It reduces the effect of the fields, as electromagnetic signals can otherwise hurt circuit operations. EMC shielding has two major elements, as follow:

Emission: Emission describes the unwanted production of strong electromagnetic signals. It must be less than the limits otherwise it can disturb the equipment.
Susceptibility and Immunity: Susceptibility and immunity refer that how equipment is going to react against the emissions.

How does EMC Shielding Work?

Manufacturers incorporate EMC shielding to prevent the interference of electromagnetic signals. The manufacturer takes the following steps to avoid interference using EMC shielding:

A metallic sheet covers the component and absorbs the strong electromagnetic signals received through the air. It can also be achieved by wrapping the transmitting device.
The covering works on the principle of the Faraday cage, as shielding enfold the component and block the electromagnetic signals.
When the shield absorbs the transmitted signal, it produces current in the screen’s body. The ground connection or virtual ground plane also receives these signals.
The absorbance of external signals keeps the sensitive circuitry protected from interference.

Factors for Choosing the Best EMC Shielding Solution

No doubt EMC shielding has a significant role in electronic devices, but choosing the right shielding is important. One should consider the following factors while choosing/designing the shield:

Mechanical Durability: The shielding should have a high resistance to mechanical and electrical failure.
Attenuation Level: Attenuation level means loss of the signal strengths. Usually, it lies between 60dB to 100dB, and some can have 120 dB as well.
Compression: The compression forces have a greater effect on the working of the equipment’s shielding properties. The compression level depends on the material.
Environmental Sealing: Protection of the component from external factors like water, dust, humidity, etc.
Complexity: The form of patterns should also be considered.
Material: There is a variety of material used in EMC shielding, so select the one based on the usage.

Materials Used for EMC Shielding

Having the right materials for EMC shielding is a crucial stage. The material choice depends on the cost, performance, specific requirements, and characteristics of the equipment to be shielded. Here are some materials that are commonly used:

Tin: Tin is an inexpensive solution and is best for lower frequency ranges. It also resists corrosion.
Copper: Copper provides the most reliable shielding solution for magnetic and radio wave frequencies. It has a high attenuation level for electrical waves.
Cooper Alloy 770: This alloy comprises copper, nickel, and zinc. It is used because of its corrosion resistance characteristics. It is ideal for MRI applications because of its permeability.
Aluminum: Aluminum costs less than other metals and is mostly used because of its non-ferrous capability and high conductance (60%).

Product Types of EMC Shielding

EMC Conductive Shielding Elastomers

Manufacturers usually shield electronic enclosures with conductive elastomers to avoid electromagnetic interference. A conductive gasket is sandwiched between a metal housing and a lid to complete the EMI shielding device. This configuration allows for adequate electrical conductivity through the gasket. EMC elastomers have high mechanical durability and heat conductivity. They are ideal for providing both EMI shielding and environmental sealing. Because of their effectiveness, EMC shielding elastomers are used in wireless transmission, military, and commercial devices.

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EMC Fingers Strip (Finger Stock)

EMC finger strips are used to ensure an excellent electric touch. These strips are of copper-beryllium material with different platings, such as nickel, stainless steel, etc. Finger strips are plated to improve the corrosion, wear, and resistance characteristics. They are resilient and have low contact resistance that results in outstanding shielding performance. Finger strips are applied in telecommunications, military, electromagnetically shielded doors, aerospace, and technical panels.

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HC Filters

HC Filters are electrical devices that eradicate the electromagnetic noise transfer between the power supply and drive. These filters can be incorporated stand-alone or on the electronic board/circuit.

EMC filters are arranged in-line, while the frequency will remove the electromagnetic interference. If the filter is a low pass, it will allow only a lower frequency. EMC filters provide applications based on their placement. Commonly, they are placed between the device and the external environment to block the entrance of undesired signals.

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Application of EMC Shielding

EMC shielding has a wide range of applications based on the value it brings. Following are some of the specific implementations of EMC shielding:

EMC shielding is used to secure medical and laboratory equipment, where disrupting and preventing signal interference is critical and potentially lifesaving. It has broad usage in the medical sector from data communications and other service transmissions to patients’ wards and theatres. It also aids in medical devices, including MRI machines and pacemakers.
As the primary purpose of EMC shielding is to prevent signals from interference, so it’s one of the common applications is to intercept the access of the data on RFID chips or other embedded devices.
EMC shielding facilitates in improving the security measures taken in military, financial, and government services.

In a nutshell, shielding is needed where any electronic equipment requires segregation from external electromagnetic signals or where there is the transmission of extra signals. In today’s technological era, every piece of electronic equipment requires to be EMC shielded.