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Techniques Used For Shielding Circuit Boards In Smartphones

 November 14, 2016  /  Comments Off on Techniques Used For Shielding Circuit Boards In Smartphones

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For several smartphone brands, product upgrades have become quite an annual ritual. Let a new kid hit the market, and gizmo-freaks make a dash for it, seeking to lap up whatever new is being offered through the latest model. Every new model brings with it a magical array of new features and an expanded list of functionalities— all packed in a smaller, sleeker space. Quite impossible to resist, isn’t it? Well, it’s the hardware and circuit boards inside a smartphone that make this wonder happen. The circuit board is the brain of a cell phone, which steers the entire system. The board itself is divided into several components that work in tandem to ensure the smooth functioning of the device.Today’s sophisticated smartphones showcase designers’ ability to successfully incorporate more in less space. However, with smartphones getting smaller and slimmer, their sensitivity to cross-talks is growing higher. This can pose a serious challenge when the phone set needs to recover very low level signals through an antenna. In addition, designers are faced with the challenge of suppressing emissions to meet strict electromagnetic radiation (EMR) and radio frequency interference (RFI) compliance regulations. This article describes several circuit board shielding techniques that can be used to block off electromagnetic waves in smartphones.

Techniques Used For Shielding Circuit Boards In Smartphones

An EMI shielding solution is designed to reflect, absorb or direct the radiated energy. There are many shielding techniques that the electronics manufacturers use to shield their smart devices against all kinds of interfering energy waves.Choosing the right technique is the key to shielding success.

Faraday Cage

These solid enclosures prevent signals from penetrating the components of a device and/ or preventing the radiating energy from escaping it. These cage-like metal enclosures cannot, however, be implemented as a standalone solution; when implementing a Faraday Cage, you will have to consider many other factors including inputs, outputs, and user interfaces. All these make their implementation highly complicated.A Faraday Cage is fit for any demanding electronic device and you can find its usage in diverse industries and applications including telecommunication, medical, and military.

Sometimes product designers prefer to create their own shielded enclosures. While doing so, they often leverage several RF accessories such as PC board mounted fingers, tables, and clips. All these ease their implementation tasks by providing both retention force and a shield ground conductive feed for the entire shielding assembly.

If creating an EMI shield from the scratch is not an option, use off-the-shelf shielding subassemblies. For example, board mounted shields, which come in a variety of sizes and shapes, are widely used on the printed-circuit boards of several devices. These ready-to-use products can easily be soldered to the boards and can be removed to gain access to the boards whenever necessary.

Mesh

Metal meshes make the ideal shielding solutions for some applications. In order to be effective, the mesh size has to be smaller than the wavelengths it seeks to block. If the mesh openings are bigger than the wavelengths, it will allow some parts of the energy wave to penetrate the device albeit in a scattered way. Off-the-shelf mesh products may be cost-effective, but metals used in them may not be suitable for your application. If you think that mesh shielding will be ideal for you application, choose the metal carefully so that it supports your specific application.

Stick-ons

An adhesive-based shielding material offers a good alternative to enclosed shields. Typically made of magnetic particles and polymer, they are lightweight and flexible, and can withstand high-temperature.

In addition, other shielding products such as tapes, ferrite materials, foils, and acrylics are used when it comes to suppressing noise or protecting low-level input signals in a noisy environment.

Electrically conductive elastomers not only shield electronics from emissions but also help absorb shock and vibration.

With the size of mobile devices shrinking and their feature-lists expanding, circuit board shielding has become a pressing issue in the field of wireless circuit designing.The techniques discussed above enable engineers to lower the susceptibility of smartphone circuits to EMR and EMI, subsequently helping them meet regulatory compliance guidelines. If you want to implement a custom shielding solution, rope in a reputed shielding solution provider who can guide you in choosing the appropriate shielding product and technique for your specific application.

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