Electromagnetic Shielding
With so many devices in the modern world emanating electromagnetic radiation, many people are concerned with the safety of these devices. Since electromagnetic products have only been in use for a few decades, it is impossible to determine if they are truly safe.
Luckily, electromagnetic shielding can block EMI and RFI radiation. Shielding comes in many forms, as thick as an actual sheet of metal and as thin as a simple coating of paint. EMI shielding manufacturers have a variety of ways to keep radiation from damaging people and sensitive equipment.
Quick Links to Electromagnetic Shielding Information
Applications of Electromagnetic Shielding
EMI shielding is used in factories to protect sensitive equipment from damage and it is used in cell phones and other personal electronic devices to prevent the waves from passing through the body. Other industries, such as the military and other safety organizations also use EMI shielding to protect equipment and people. Certain shields and coatings are used for tasks like preventing waves that can trigger harmful devices and disrupting pulses that can damage sensitive electronics. Some coatings are simply necessary to prevent two forms of waves from interfering with one another, such as the waves produced by two different machines in a factory.
Without the protection that EMI coatings and shields provide, many industrial companies would have a lot more problems. Machines that interfere with one another could cause expensive damages. Radiation passing into workers could potentially cause health problems. It is essential to protect the equipment and people in a factory or any commercial setting from the potential of EMF or RFI radiation.
How Electromagnetic Shielding Works
Electromagnetic shielding is a barrier which protects electronic equipment from ambient electromagnetic interference. Electromagnetic interference, or EMI, is the magnetic field which is created by electrical currents. EMI can travel along wires, electrical circuits, and conductors, while radio frequency interference (RFI) is radiated electromagnetic noise, which travels through the air as radio waves. Both EMI and RFI cause similar effects, although EMI typically operates on lower frequencies than RFI.
Types of Electromagnetic Shielding
EMI enclosures, EMI coating, EMI gaskets, and EMI filters are used as magnetic shielding to guard sensitive electronic equipment. EMI and RFI are created by everything that conducts electrical energy, including electrical wires, electrical appliances, computers, and all electronic equipment. Signal-bearing electronic devices such as mobile phones give off RFI.
Normal electrical currents are disrupted when moderate to high levels of EMI or RFI are introduced. Un-channeled electromagnetic signals and radio frequency waves can act as “noise,” magnetically altering normal flow of electrical currents and impeding the flow of electrical energy. Electromagnetic shielding and EMI filters can be found in medical devices, computers, mobile phones, stereo systems, television sets, windows, vents, fabrics, foils, and even walls.
Materials Used in Electromagnetic Shielding
Shielding sensitive electronic equipment from electromagnetic interference and shielding high EMI-emitting equipment from contaminating other equipment can be achieved by enclosing equipment in a conductive EMI absorbing material or by coating equipment or enclosures with EMI coating. Thus, electromagnetic shielding can be accomplished through evident physical objects or through unapparent objects. Electromagnetic shields are also called magnetic shields, EMF shields, or RFI/RF shields and may be made from conductive rubber, like nitrile or silicone, or metals with high magnetic permeability.
Metals such as nickel, copper, steel, and aluminum are commonly used, although the industry standard magnetic shielding material is Mu-Metal®, an alloy of nickel, iron, copper, and molybdenum. Many industries depend on EMI shielding products to protect communication systems in industries such as medical, telecommunication, stage production, sound production, and many others. Within circuit boards and CPUs, most problematic EMI comes from electromagnetic cross-talk between different components on the same board as EMI travels across wires and conductive materials.