EMI/EMR Shielding Techniques, Design and Application

0
1932
Mobility and modern telecommunication concept: macro view of tablet computer and touchscreen smartphones with colorful interfaces on laptop notebook PC

The advanced features or functionality of personal computers, laptops, smartphones, tablets or iPods have made our lives easy, but with compact silicon geometrics, susceptibility to noise is getting higher. Besides protecting us from unwanted noise, engineers also need to reduce or stop electromagnetic interference (EMI) and electromagnetic radiations (EMR) emanating from the devices. This means that the electrical devices or appliances we use must have integrated EMI shielding material to thwart emissions, as well as meet radio frequency interference (RFI) and EMR compliance statutes and guidelines. Read on to learn about the shielding products and techniques to control the levels of emission.

The Faraday Cage

A shielding design and technique are the necessary prerequisites to stop EMI. With the Faraday Cage, you can ensure superior shielding. However, there are inputs, user interfaces and outputs making the shielding process challenging. Fortunately, there are well-engineered and custom-designed sub-assemblies to make EMI shielding more effective.

Shielded Enclosures with RF Accessories

If you want to design personalized shielded enclosures, you’ll find RF accessories to make your job simpler. These accessories include tables, PC board mounted fingers and clips. First-grade springy clips offer good retention force for any shielding assembly, and also provide a shield ground conductive feed.

As far as board-mounted shields are concerned, they’re available in a range of shapes and sizes that can be integrated on any printed-circuit boards. The shielding material can be fastened to the boards. They come with vent holes to help in outgassing during the process of soldering. You’ll also get peel-away top coverings to get access during the process of development. You can also seal the tops electromagnetically, if required. Make sure that you use the best enclosure as some signals may radiate or interfere. Look for an EMI/EMR shielding product supplier that offers attenuation plots indicating the levels and frequencies at which an enclosure attenuates.

Application

The metal-formed enclosures, mini cages and related products are used in telecommunications, medical, radar, telemetry and community access television (CATV) applications. These products also let you leverage the standard printed-circuit board technology and help you to attain a relatively compartmentalized partitioning. The strongest and most ingeniously designed Faraday cage enclosures are used in military applications for security reasons, particularly for coding and communication purposes.

Use of Compartmentalized Metal Enclosures

Products such as compartmentalized metallic enclosures along with smart geometric positioning help in segregating the functional stages, as well as managing the flow of signal. Every stage that emits electromagnetic radiations is fully enclosed, and the signals move from one stage to another via feed-through capacitors. High-quality feed-through capacitors help you to make low-pass, high-pass, band-pass, and notch filter types via the interconnects from one stage to the other. As far as a press-fit leadless capacitor is concerned, it can be employed in an automated fabricated surrounding. For low-noise and chassis-partitioned designs, the filter parts help in reducing emissions, and are available in leadless, leaded, hook, turret, press-fit and soldertail configurations.

This kind of protection is necessary only for the most sophisticated products. For most of the applications, you need low-cost, simple and lightweight EMI shielding material.

Mesh is a Good Option

In a few cases, mesh is a great option for reducing electromagnetic radiation and interference. This is possible only if the size of the mesh is comparatively smaller than the wavelengths. On the contrary, if the wavelength is smaller than the mesh, the electromagnetic waves will invade or interfere at a somewhat attenuated or interspersed level. Do not go for low-quality mesh material that are easily available and are too cheap. They lack the characteristics that are essential to design a quality shielding product. These materials also weather and break over time.

With more electronic devices flooding the market and circuit board size shrinking, you need quality EMI shielding material to protect your devices from interference and damage. It is best to trust a solutions provider with good clientele and years of experience in this field.