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5 EMI Shielding Techniques Today Explained
EMI shielding techniques range from enclosure shields and conductive film to shielded cables. Each of these methods has its own advantages. Depending on the specific application, one may offer better protection than another. Read about the five common EMI shielding methods in use today below, and how they help reduce interference levels.
Table of Contents
What is EMI Shield?
Let’s begin b looking at the EMI shielding definition. An EMI shield is a protective material used to reduce the amount of electromagnetic interference (EMI) that escapes or enters an electronic device. EMI shielding helps maintain compliance with various industry standards, such as FCC. This type of shielding also prevents electrical equipment from interfering each other. To understand how it works, here’s the EMI shielding theory and mechanism.
EMI Shielding Theory
Electromagnetic Interference, EMI, is used to refer to a phenomenon that occurs when EM waves cause unwanted effects. This usually happens when one device or component interferes with the signals or operations of another nearby device or part, leading to electrical noise or distorted signals.
EMI shielding is, therefore, necessary to prevent the adverse effects caused by electromagnetic emissions. It involves using materials such as conductive foils, metal coatings, or enclosures that prevent or reduce the transmission and reception of these waves, thereby providing protection for the device in question.
EMI Shielding Mechanism
The EMI shielding mechanism involves either a reflection or absorption of the electromagnetic waves — usually by creating a conductive barrier around the specific device or product. This is common in range of industries, including aerospace, defense, and telecommunications, where it’s critical to ensure safe and efficient operations.
To maintain an effective EMI shielding, it’s essential that engineers follow industry best practices. In cases of EMI leakage, for example, locating and removing the source of the interference, or using additional shielding materials, can help restore the performance of the affected device or system.
EMI Shielding Techniques
EMI shielding is an essential concept in modern electronic design. To achieve it, various shields and shielding methods are used, and each of them has its own advantages in certain applications. Here’s an overview of five EMI shielding techniques commonly seen today:
EMI Shielding Enclosure
An EMI shielding enclosure is simply a box or other structure that is used to isolate sensitive electronic components from electromagnetic interference. The enclosure acts as what’s called a Faraday cage, reflecting and dissipating the electric fields generated by nearby devices or systems.
An EMI shielding enclosure can be many design designs, depending on the usage need. It can be a small EMI shielding box in a portable device such as smartphone or a larger, a large structure for industrial applications.
Also related to this shielding method is the EMI shielding tent, which is mostly used for testing purposes. This type of protective enclosure is used to contain and isolate electromagnetic fields generated by the test equipment, so that it does not affect any other components in its vicinity.
EMI Shielding Film
An EMI shielding film is a thin layer of conductive materials that’s applied directly to the surface of a product or device. The film provides protection by blocking the electromagnetic waves that are emitted from different sources, thus reducing their effects on the device.
An EMI shielding film can be made from different materials. It can be a conductive EMI shielding paint that’s sprayed on the product, conductive ink, or an adhesive EMI film that’s applied directly onto the surface of the device. They films are usually very thin, which makes them well-suited for an array of applications.
Most often, an EMI film is applied to RF electronic devices or plastic EMI enclosures. In addition to allowing for less costly shields, this is one of the EMI shielding techniques that will often be used where weight is a primary consideration, such as in electronics.
EMI Shielding Gaskets
This is one of the most common EMI shielding methods today. An EMI shielding gasket is a flexible, conductive material serves to absorb or dissipate EM interference.
It is usually made of metal or a conductive elastomer that has been designed to fit around the edges of an electronic device, forming a tight seal between the device and the surrounding environment.
EMI shielding gaskets are often used in conjunction with other forms of EMI shielding, such as an EMI shielding enclosure or a shielded room. They are also used to provide shielding in small, tight spaces where other techniques may be too bulky or not cost-effective.
EMI Shielding Mesh
An EMI shielding mesh is a protective covering made of woven metal, usually copper or aluminum. It works by reflecting the electromagnetic waves away from the protected device or system and reducing the amount of interference that reaches it.
The mesh can be used in a variety of applications and is often applied to the external surfaces of devices or systems. It is also sometimes employed as part of an EMI enclosure, providing a layer of protection against unwanted emissions.
When used for electromagnetic shielding, meshes provide a flexible and low-cost solution for many applications. They are lightweight, durable, and can be easily customized to fit a variety of shapes and sizes. The size of the mesh, in particular, can be adjusted to accommodate different levels of interference or wavelength.
EMI Shielding Cable
Among the many EMI shielding techniques, one of the most common is the use of shielded cables. This type of cable consists of a single or multiple conductor wires that are surrounded by a conductive shield.
The shield may be a braided mesh covering a signal or power cable, or it can be a layer of tape wound along the length of a cable. The shield is typically made of metal, such as aluminum or copper, and designed to suit the specific application of the wire.
EMI shielding cables can be used to provide a high degree of protection from interference, as well as reduce the amount of signal loss or crosstalk between adjacent cables. They are also relatively easy to install and require minimal maintenance over time.
Conclusion
These are just some of the most common EMI shielding techniques available today. Depending on your application, any of these methods may the best way protect your sensitive electronics or systems. Sometimes, an EMI shielding method is be used alongside another, depending on the protection or EMC requirements at hand.