It’s a question we get asked a lot, and understandably so – there are a lot of strange products out there with little science to back them up. This is not how we operate. All of our products work and, better yet, they can be tested and proven to work.
All of our fabrics, including bed canopies, clothing, sleeping bags, etc., all work on the same basic principle. They have metal woven into the fabric, usually silver, and this then creates a barrier that can block electromagnetic fields such as phone signals and WiFi.
On the surface level, that’s all there is to it. The tricky bit for us is making the metallic component incredibly thin so that it can be woven straight into the fabric. Plus, there is a lot more to the science, including the wavelength you are trying to block and the corresponding size of mesh needed, and we will dive into that later in the article.
Faraday cages are a big buzzword in the world of electromagnetic fields (EMFs), but what exactly are they? A Faraday cage, simply put, is an enclosure created to block EMFs. The Faraday cage was invented by scientist Michael Faraday, hence the name.
A Faraday cage must be constructed from a conductive fabric like our BlocSilver EMF Protection Fabric. When an electromagnetic wave hits the conductive surface of the Faraday cage, instead of passing through it, it gets dissipated around the exterior of the cage. This cancels out the field’s effect on anything inside the cage, thus eliminating EMFs inside the cage. When paired with one of our bed mats, our BlocSilver EMF Bed Canopies create a Faraday cage.
This well-known scientific phenomenon is widely used in day-to-day life, probably without you ever noticing. A microwave oven, for example, uses this principle to stop deadly microwaves from escaping and cooking your body as well as your dinner! Faraday cages are also frequently used in high-tech electricals to protect delicate electronic equipment.
Grounding of a Faraday cage is essential to dissipate the blocked electrical currents; this is why if you are creating a Faraday cage from our canopies it is essential to properly ground it.
One quirk of Faraday cages is that they block incoming signals a lot better than they do outgoing ones. What this means in practice is that a mobile phone inside the canopy may still be able to receive a signal due to it transmitting out of the canopy. This is why testing the effectiveness of a canopy with a mobile phone is not a good idea – always test the effectiveness with an EMF meter.
If you were purely trying to block out every electromagnetic frequency, it would be better to build a solid Faraday cage, but it wouldn’t create a nice sleeping environment. That is why our canopies are made of a mesh fabric, leaving them light and airy. There is always a delicate balancing act between protection and the creation of a pleasant sleeping environment.
The size of the gaps in the mesh is directly linked to what size of wavelength can pass through it. This is why a fabric that shields well at 3 GHz may perform poorly at 30 GHz. The shorter the wavelength, the more easily it passes through a mesh of a given size. This is why the performance of EMF blocking fabrics will drop off (at widely varying rates) at higher frequencies.
For effective shielding the mesh size should be between 10-20 times smaller than the wavelength. For example, a 2 GHz signal has a wavelength of 150 mm so you would need a mesh size of between 7.5 mm and 15 mm to block it, which is quite wide. However, when we start talking about 5G signals in the 40 GHz range, we need a much smaller mesh. A 40 GHz signal has a wavelength of 7.5 mm so you need a mesh size of between 0.37 mm and 0.75 mm to fully block it.
One huge bonus of selling products that work according to understood and accepted principles is that they can be tested. Which is exactly what we do! Check out these test reports for many of our fabrics. Please note that some of our fabrics have only been tested at lower frequencies – these are our older fabrics and there was simply no need to test them at higher frequencies at the time. Rest assured we are working on new tests at higher frequencies, and the results will be released shortly.
Click the images below for the shielding reports.