Finding the Right RF Shield for Any Application
RF shields are an incredibly important part of modern electrical design. Systems of all kinds require RF shielding to prevent interference and ensure proper operation.
From medical devices to telecommunications, the applications of modern RF shields are endless. Choosing the right RF shield for any given application requires careful insight into the specific needs of that application and its unique design constraints.
Different Types of RF Shields
Today, there are many different types of RF shields and shielding configurations that can provide protection for different types of devices and applications.
The first RF shields were simple Faraday cages consisting of wire mesh or screens around electrical components.
While these still see use in some applications today, a much wider range of options has emerged.
Among the most common types of RF shields available today are solid enclosures. These are versatile and well suited to an extensive range of applications.
They often accomplish multiple design requirements simultaneously, providing RF shielding and also a strong and sturdy enclosure.
A solid enclosure is simply a casing or container made from a continuous piece of metal or multiple metal pieces that fit together. The enclosure can be carefully developed to the unique shape required for any design and can include a variety of openings for cables and other auxiliary components.
A solid enclosure blocks a very wide range of electromagnetic frequencies. They are among the simplest options to implement, useful in many applications without modification or custom design.
As the RF waves come into contact with the solid enclosure, it safely diverts stray currents on its surface to the ground.
In some cases, additional protection is required. Very sensitive applications must also shield openings that allow for cables to pass through solid enclosures.
This can be accomplished with RF shielding gaskets and O-rings at seams and openings. These gaskets can be made of metals similar to solid enclosures or more elastic materials with embedded metal.
While a solid enclosure can protect a specific device or component, the cables that run from that device to other locations are still susceptible to interference.
This is particularly important where sensitive signals are concerned.
Cable shielding is integrated into the insulation around cables to protect against interference. It can take the form of a foil or spiraling or braided wires.
Each style has advantages and disadvantages in terms of flexibility, durability, and shielding effectiveness.
RF Shield Materials
An RF shield can be made from essentially any conductive material. However, some are more effective than others, and requirements can vary depending on individual applications.
They are often alloys of different types of metals or structural metals with an additional coating.
Tin-plated steel is among the most cost-effective materials for RF shielding. It provides shielding against a wide range of electromagnetic waves.
The tin plating makes the RF shield corrosion-resistant and enables easy soldering, making it perfect for an extensive range of applications.
Nickel-silver RF shields are made from a specific alloy that contains nickel, copper, and zinc. It doesn’t actually contain silver but is called nickel-silver due to its bright appearance.
It provides exceptional corrosion resistance and shields against a wide range of frequencies. It also has the appropriate magnetic permeability value for applications like MRI machines.
Choosing the Right RF Shield
When choosing an RF shield for any application, there are several key criteria to consider. The specific range of frequencies that must be blocked is important, as is the tolerance that the electronic components can handle.
In large-scale production, cost becomes an important factor, and manufacturers must also consider the physical dimensions of any RF shields and how they fit into their design.
Luckily, there is a robust selection of RF shields available to fit any application’s unique needs.
Posted in Technology