Effects of RF Radiations from Mobile Towers and Mobile Phones

Wireless Communication and RF communication are used as synonyms as all wireless communications use RF frequencies. RF frequencies cover a frequency spectrum of 3KHz to 300 GHz in complete Electromagnetic spectrum. Wireless Communication is the mostly popular and most widely used communication system in the world today with its application ranging from Mobile/Cell phone communication, short distance communication like Bluetooth, NFC, Wi-Fi and very long distance communication like satellite commination, GPS etc. Unarguably one of the most important (commercially) application of wireless communication is Mobile Phone communication with number of mobile phone subscriptions would easily be more than the population of the planet Earth today (as per Wikipedia, in 2010 there were more than 6.6 billion mobile subscriptions). The service provider continually face this challenge of meeting the demand of increasing number of users and to provide them quality and reliability of service. Network service providers try their best to provide high data rate, increased network capacity and high mobility to each and every customers and as a result we see a large number of Mobile Towers or Base Stations being installed at very fast rate.

Figure 1: RF Radiations from Mobile Tower and Cell Phone

RF radiations emitted from Mobile Towers and Mobile phones as illustrated in Figure 1 surely have some harmful effects on human beings. These effects are studied and documented by many researchers. Exposure to RF radiations could cause heating of biological tissues that leads to an increase in the body temperature and it is called Thermal Effect. Eyes are more vulnerable to thermal effects and could result in blindness. Although our body can regulate the temperature on its own but prolonged high exposures make the body unable to adapt. There are some non-thermal effects also that include increased cell proliferation, changes in hormones and immune system, heart and other nervous disorders. Medical devices such as pacemakers could also experience interference from mobile phone radiations and it is called Electromagnetic Interference (EMI). EMI could affect the performance and working of medical devices.

Specific Absorption Rate or SAR gives a measure of the amount of RF energy absorbed by the tissues in the human body. It is measured in Watts per Kg and indicates the average rate at which energy is absorbed for each kilogram of tissue. SAR estimation is utilized to decide if a cell phone's radiations' adhere to the safety guidelines or not. For example, the permissible SAR level in USA is 1.6 W/Kg and in Europe, manufacturers make sure that the SAR value does not exceed 2 W/kg. ESM 120 is a unique measuring head the enables the real time measurement of SAR. Below is a picture of SAR Meter ESM 120. It comprises of an estimating head with a HF sensor, the body with working controls, LC display and optical interface. Display shows current SAR as decimal value and as a bargraph. There are other instruments like Spectrum analyzers and broad spectrum meters that are also used for the determination of high frequency fields and RF radiation levels.

Figure 2: SAR Meter-ESM-120

Instruments like these which are used for quick determination of SAR in Mobile Phones, Base Stations, Antennas and other Wireless Systems find applications in research, development and training. A few examples are Finding faults in devices, Estimating critical radiation values in Airplanes, Tunnels and now in Cars, Informing users to make low radiation calls by holding the device correctly etc.

By: Ms. Ashu Taneja - Assistant Professor (ECE), Chitkara University, H.P.

References

1. L. Pachuau and Z. Pachuau, "Study of Cell Tower Radiations and its Health Hazards on Human body", IOSR Journal of Applied Physics,Vol. 1, No. 1, 2014.
2. https://www.cpwr.com/sites/default/files/research/3._Health_Effects_of_RF_Radiation.pdf
3. http://www.doh.gov.uk/mobilephones/index.htm
4. http://www.iarc.fr
5. http://www.rsc.ca/english/RFreport.pdf