Measurement and Evaluation of Electromagnetic Radiation Exposure from Antennas in Cellular Networks
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Date
2021-07
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KNUST
Abstract
Wireless Technology including that of cellular systems uses radio and microwave energy which is nonionizing in nature, generated at base stations for its transmission via cellular antennas and microwave links to accessible areas for subscribers. The nonionizing radiation (NIR) energy is absorbable by living tissues including human skin and thus, becomes harmful when it exceeds certain thresholds.
The health risks associated with exposure from base transceiver stations has gained attention as the demand for cellular services increases. This has led to an increase in communication infrastructures (Base Transceiver Stations), ushering some in human inhabitance to improve quality of service, as these services become a vital part of modern lifestyle. An increase in base transceiver stations, leads to increased cellular radiation pollution which is of public concern. It is therefore necessary to investigate the levels of cellular radiation to ensure that it public health safety limits are not violated.
In this thesis, NIR level in power density at forty locations involving residential, commercial and University campuses, considering indoor and outdoor scenarios were measured and estimated with a radio frequency (RF) Explorer 6G Combo Spectrum Analyzer. The results were compared with the minimum safety limits of 4.055 W/m^2 for cellular systems in Ghana, formulated by the International Commission and Non-ionizing Radiation Protection (ICNIRP) and enforced by the National Communication Authority of Ghana (NCA).
The maximum total level of radiation consisting of a cumulative of all deployed systems was found to be 862.9 (nW/m^2) for residence near base stations during evening hours and 242.6 (nW/m^2) at day time. The maximum and minimum levels recorded for other locations are 3.96 (nw/m^2) and 0.10 (nw/m^2) at residence away from base stations, 118.5 (nW/m^2) and 0.422 (nW/m^2) for commercial areas and 38.92 (nW/m^2) and 4.97 (nW/m^2) at the campuses. A standard deviation of 49.9 at three different sectors of a single base station was achieved. A highest radiation level of 305.6 (nw/m^2) was recorded at 7 pm of the 24-hour indoor measurement, while the cumulative average of 160.5 (nw/m^2) was recorded at the 24th hour.
A percentage of the highest 862.9 (nW/m^2) radiation level recorded is less than 1% of 4.055( w/m^2) minimum safety limits recommended by the International Commission on Nonionizing Protection (ICNIRP). Thus, cellular system radiation emissions of the selected locations do not pose any health threat to the general public in their current capacity.