Do you want to know how shielding boxes can help you in EMC compliance testing for your products? If so, you have come to the right place. In today’s blog, we will delve into shielding boxes and why you need them when taking electronic gadgets through the EMC compliance testing regimen.
What Is Radio Frequency Shielding?
Radiofrequency shielding is the practice and process of using specialised pieces of equipment to block radio frequency interference. The specialised equipment used in the shielding process is an enclosure designed to prevent magnetic and electric transmission to and from the chamber.
In doing this, the enclosure protects any electronic device held therein from inference from the radio frequency disturbances from devices within its vicinity. At the same time, the shielding box lowers the radiation frequency that leaks outside and interferes with other devices.
Understanding RF Shielding Boxes
Also known as a test chamber or RF test chamber, RF shielding boxes typically use magnetic and conductive materials to achieve shielding. The shielding box is generally lined with metal foam, metal strips, and/or metal screens. The choice of metal used in manufacturing the shielding box depends on the level of shielding the RF shielding box must meet.
Some of the metals popularly used in the manufacture of RF shielding boxes include:
Copper – Copper is the most prevalent metal used to manufacture RF shielding boxes because of its versatility. The materials are highly conductive, making them highly appropriate for shielding. It also does not corrode or oxidise quickly. Copper alloys, mainly brass, bronze, and beryllium alloys, are also used to manufacture RF shielding boxes.
Steel – Mild and annealed steels provide low-frequency magnetic shielding.
Aluminium – Aluminium is used when the shielding box needs heavier gauge metal and when the RF shielding box needs a metal with high strength-to-weight properties.
Other materials used in manufacturing RF shield boxes include nickel silver, conductive elastomers, and pre-tined steel.
Aside from choosing suitable materials for shielding, the quality of manufacturing is also critical to achieving the proper levels of shielding. For instance, the manufacturing process shouldn’t leave seams and penetrations in the shielding box. Seams and penetrations are points of shielding deterioration.
Additionally, it’s essential to ensure the shielding metals are protected from oxidation and galvanic corrosion.
RF Shielding Using Shielding Boxes
The effectiveness of a particular RF shielding box depends on the shield’s thickness, its design, the shielding materials used, and the presence and size of discontinuities on the shield. Furthermore, shielding boxes do not offer a universal level of shielding across the electromagnetic spectrum.
Different shielding boxes are optimised to block electromagnetic frequencies of specific ranges. A shield with high magnetic conductivity enables the shielding box to reflect or block the electric component of the waves. On the other hand, a shield using materials with high magnetic permeability will benefit from the least reluctance path for magnetic flux. This enhances the ability of the shield to absorb the magnetic fluxes.
With the above in mind, RF shielding boxes are used to validate that the device under test does not produce radio frequencies (electromagnetic noise) that will disturb the proper functioning of other electronic devices. The RF shielding box is used to validate that the device under test is also resilient to radio frequency interference from radio frequencies produced by natural sources and man-made devices.
RF shielding boxes are used to test that the device being tested does not experience radiation, conduction, capacitive, and magnetic coupling. These are different ways that the interfering electromagnetic wave can interact, causing electromagnetic interference.
RF shielding boxes are designed to help manufacturers of electronic appliances and equipment make sure they are safe and will not cause or experience electromagnetic disturbances. For the industry-leading RF shielding boxes and testing, Compliance Engineering is here to help.
Compliance Engineering operates an internationally accredited EMC testing laboratory and has decades of EMC compliance experience and can help you achieve compliance with appropriate EMC standards for products that are to be exported or sold locally. Our services include EMC testing and compliance, radio testing, antenna calibrations, on-site EMC measurements, and EMC consultancy, among others.