Purpose: To receive and transmit audio and video signals.
Issues: Cell phones contain an antenna for: cell signals, WiFi, GPS, blue tooth, IR, and radio. I take that to mean that each of these frequencies can cause a potential issue.
SAR: All phones have something called an SAR rating. Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field; although, it can also refer to absorption of other forms of energy by tissue, including ultrasound. It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).
Source: ken-foundation-awareness.blogspot.com
SAR ratings are calculated by the manufacturer for each phone. Usually the SAR rating is determined with the phone 10-15mm from the body. That means that you hold the phone AWAY from your ear. If you press it TO your ear, the SAR rating does not apply (or is not accurate). Obviously, a phone with a lower SAR rating is a better choice. The SAR rating is just about the HEATING of the tissue. It does not indicate the other possible issues that can arise from electric and magnetic fields generated by the phone.
Cell phones use transmission frequencies in the microwave range. These frequencies, while not the same as those used by a microwave oven, are still in the same spectrum and do casue tissue heating. The phone antennas are NOT directional. That means that they transmit into your head when you use the phone. (let that sink in for a bit)
Frequency Range:
Better Option: Unfortunately, in todays society, there is not another option. Land lines, which are safer from an EMF perspective, are harder and harder to find. We have become so ingrained to smart phones and the technology they bring that we are unlilkey to give it up. So, the best option is to use the phones wisely. First, don’t place them up to your ear - always use a handset or handsfree option. Using a phone for texting is a better option than holding it to your ear. Keeping it turned off or in airplane mode is the best option to limit your exposure. See Quick Tips for even more information.