Are you interested in radio frequency (RF) enclosures? Do you want to know what RF shielded enclosures are and what their uses include? Every single electrical or electronic circuit produces electromagnetic waves (EM) and the components in electronic products are also susceptible to interference from EM waves from various sources. RF shielding enclosures are used in these products to prevent unnecessary transmission of EMI and to protect the internal components from EMI.
In today’s blog post, we will discuss RF shielded enclosures and their uses. Continue reading below to learn more!
What Are RF Shielded Enclosures?
As explained in the beginning, the components in an electronic product are prone to interference from electromagnetic signals. RF shielding is the practice of enclosing electrical or electronic circuits inside a barrier to prevent this interference. The goal of shielding is to completely isolate these components from the outside environment.
RF shielded enclosures are made from a variety of materials and the choice of the material depends on the design, electromagnetic frequency, thickness needed, and other parameters.
Without RF shielded enclosures, electronic and communication devices are prone to performance issues and may result in security breaches, loss of data and, in extreme cases, complete failure of devices. Since all electrical circuits are capable of emitting electromagnetic signals and are also susceptible to EMI, RF shielded enclosures are designed to keep the components and devices safe from RF interference.
Sources of Radio Frequency Interference
RF interference can happen due to natural sources as well as man-made sources. Examples of natural sources include dust storms, static electricity, lightning strikes, snowstorms, solar flares and cosmic noise, among others.
All electrical and electronic devices are capable of emitting electromagnetic waves that may affect other equipment within a particular distance. There are intentional and unintentional man-made sources.
Examples of unintentional sources include lighting, electric motors, satellites, transmission lines, inverters, and so on. Other sources include wireless routers, Bluetooth speakers, laptops, mobile phones, remote controls, and other such common devices. Intentional sources of RFI include jamming devices, radars, radio transmitters and so on.
Materials Used for RF Shielded Enclosures
The effectiveness of RF shielded enclosures depends on the certain properties of the material used, the geometry of the enclosure, as well as electromagnetic wave frequency. Magnetic permeability and electrical conductivity of the material play a huge role in the effectiveness of the shield. Common materials used for RF shielding enclosures include:
1). Copper – Copper is known for its high electrical conductivity. It is one of the most reliable materials due to its effectiveness in absorbing magnetic and electric components of EMI. Copper is readily available and can be easily formed into a variety of shapes. It is also capable of resisting oxidation and corrosion. Various alloys such as brass, bronze, beryllium copper, and phosphorus bronze are widely used for RF shielding enclosures.
2). Nickel silver — Nickel silver is an alloy containing copper, zinc, and nickel. It has a magnetic permeability of 1 which makes it perfect for use in MRI machines. This alloy is an excellent choice in corrosive environments.
3). Aluminium — Aluminium is capable of blocking low-frequency electromagnetic waves. In terms of conductivity, it is at 50 to 60% of copper. This means that equivalent aluminium shielding needs to be almost twice as thick compared to copper shielding for same the effectiveness. Aluminium is also prone to natural oxidation and galvanic corrosion.
4). Steel — Steel is a ferromagnetic material. It is capable of shielding from low-frequency EMI which makes it a better choice than copper alloys and aluminium in certain situations. There are different types of steel depending on its constituents.
A few other materials used for making RF shielded enclosures include Mu metal, conductive elastomers, and conductive fabrics, among others.
In summary, RF shielded enclosures are used to block electromagnetic interference to prevent any effects on the performance of electronic devices. Strong EMI may even lead to the complete degradation of an electronic device. A variety of materials are used to make these enclosures and these materials are typically chosen on the basis of their electrical conductivity and magnetic permeability properties.
Compliance Engineering is an accredited laboratory for EMI testing. Our experts will be happy to discuss the details of EMI testing that is applicable to your products.