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Absorption Of Electromagnetic Energy – An Overview

Electromagnetic interference is the energy that causes unwanted noise affecting the performance of any equipment present in an environment. Over the years, scientists have developed many different composite materials for EMI shielding. Several factors may cause the generation of this type of energy –tension circuits, circuit breakers, fluorescent lights, microwaves devices, mobile devices, and more. Researches are still on for creating new alloys that can reflect radiation. Ideally, any conductive material which shows flexibility makes good candidates for EMI shielding. As per this requirement, flexible metals like graphite can be included into the list of EMI shielding materials. However, shielding products made of most of these materials are bulky and are therefore unsuitable for use in today’s sleek electronic devices. Though some alloys are lightweight, they may not be very good at absorbing radiation. Recently, a team of researchers at MIPT, Kansas State University, and the US Naval Research Laboratory has come up with a groundbreaking invention – an anisotropic crystal – that would allow shielding solutions to absorb electromagnetic radiation fully. In addition, there are many other materials that facilitate the effective absorption of electromagnetic energies. This article will help you understand how these materials work.

Absorption Of Electromagnetic Energy – An Overview

What Decides a Material’s Shielding Effectiveness?

The effectiveness of electromagnetic shielding, to some extent, is determined by a shielding material’s ability to absorb the radiated electromagnetic energy. From photovoltaic industry to the aerospace sector and from electronics to medical devices – containment of electromagnetic energy is essential for the efficient functioning of products.

Traditionally, people used the good old black paint to absorb electromagnetic energy. Let us consider this example for understanding how it is used for blocking sunlight. The color black itself absorbs light that falls on its surface. However, it does not happen to be a very efficient absorber. It cannot absorb the energy completely. As a result, the portion that is not absorbed (incident light) is reflected back into the environment.

Basic Qualities of EMI Shielding Materials

When it comes to absorbing electromagnetic waves, shielding materials should be highly conductive and consist of hollow carbon microspheres. If it does not belong to any naturally occurring metal molecule group, such a material can be manufactured with the inclusion of a coal or petroleum-based pitch material into its chemical structure. Both of these elements need to be non-cohesive to one another. When a non-conductive material is mixed with a non-conductive one, the mixture is turned into moldings. The resultant composite achieves high-level dielectric properties. A composite material, born in this way, can be used as an efficient microwave absorber for a range of applications including waveguide, heating range, and antenna.

Today’s most widely used electromagnetic wave absorbers generally leverage carbon black and a synthetic resin substance. While the former works as a conductive material, the latter serves as a non-conductive material. However, in these materials, particles are not arranged uniformly. They tend to form lumps which, in turn, prevent the formation of a seamless conductive material. These local irregularities affect the electrical features of the EMI shields. This system makes it overly difficult for designers to address dielectric loss factor. They end up causing an increase in the dielectric constant, which is undesirable.

Any electronics application needs appropriate materials for creating EMI shielding solutions. In the absence of the right material, the product may fail to offer enough protection, subsequently damaging the performance of the system for which the shield has been designed in the first place. The spilling of electromagnetic energy can be a source of grave danger in some instances. It is therefore highly recommended that you hire only experienced professionals for developing a shielding solution for your application. Only a qualified designer can guide you on choosing the most suitable material for your application needs.

  • Aug 1, 2017
  • Ryan
  • News
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