4.2. Shielding against EMF-emitting devices
Another recent phenomenon is a variety of products appeared on the market called "health chips", "EMF radiation protection chips", "mobile phone shields", etc., that supposedly reduce the adverse health effects of mobile phones by "reducing radiation levels" or "reducing the gradients of the magnetic fields" or "smoothing the peaks", or "alter the radiation into a form that does not produce adverse health effects", or "transform and neutralize the harmful effects of EMFs by radiating a protective field when placed directly on devices", etc. These are usually in the form of patches that the users should stick on their mobile phones and other electronic devices, supposedly protecting them from the radiation emitted by these devices. This does not seem to bear any scientific explanation.
One cannot modify the radiation (frequency, waveform) once it has been emitted by a device. One can only attenuate it (reduce its intensity). Modification would only be possible by modifying the electronic circuits within the devices. Even if that were the case with these products, which is not, once the emitted signal is modified or attenuated, the device (mobile phone, etc.) would lose its ability to connect with the network and communicate. If one simply attenuates the signal without modifying it, which is possible, the mobile phone again will have difficulty in establishing connection with the base antennas and automatically will emit a stronger signal/radiation/EMF in order to be able to connect/communicate (Panagopoulos, 2011). This is why it is dangerous to put the mobile phone within any kind of metal box/sheath/holster etc. in order to carry it on the clothes/body while it is turned on. Any such product will attenuate the incoming signal, and thus it will attenuate the connectivity of the mobile phone. The less the connectivity is, the stronger the emission of the device becomes in order
to be able to connect with the network.
Therefore, it hardly makes any sense that sticking a patch on a mobile phone or any other electronic device would have a protective effect on the user. On the contrary, it may increase risk. As with metal patches on the walls, metal patches on mobile phones and other EMF-emitting devices may increase exposure due to "corner effects", and interference at unpredictable locations. Thus, they should be avoided.