ENVIRONMENT PHYSICS ESTIMATED AND MEASURED VALUES OF THE RADIOFREQUENCY RADIATION POWER DENSITY AROUND CELLULAR BASE STATIONS  S. MICLAUS 1 , P. BECHET 2 1 Land Forces Academy, 3–5 Revolutiei St., 550170 Sibiu, Romania, miclaus@armyacademy.ro 2 Communication and Informatics Center, 1–3 V. Milea St., 550325 Sibiu, Romania Received September 12, 2006 Theoretical and experimental assessment of radiofrequency exposure due to cellular base station antennas is treated. The calculation of the incident power density of the radiation flux is possible by knowing the antenna’s technical data from the constructor and by defining the position of the exposed person. The free space propagation model in ideal conditions yet allow just a gross assessment of exposure in the far field region of the antenna, which generally overestimates the real exposure level. Exposure assessment may be also theoretically calculated in near field conditions, with a better agreement with real cases. The compliance distance from the antenna is another important parameter and it can be calculated in accordance to the reference levels stipulated in exposure standards. From experimental perspective, far field in situ measurements of power density level were made in a limited number of locations, by using the frequency-selective method and equipment. The results are discussed, regarding both the obtained values and the factors that influence the measurements. The measured values were well bellow the maximum permissible exposure levels in the adopted standard in our country. Key words: radiofrequency, mobile communications, human exposure, power density, base station antenna. 1. INTRODUCTION In the last decade, the massive proliferation of mobile communications equipment raised a special concern regarding the safety of population and personnel exposed to radiofrequency (RF) radiation emitted by either the cellular phone terminals or the base-station antennas (BSA) [1]. Exposure standards for RF region of electromagnetic spectrum, applicable at national or international level give, for the UHF band of interest, the rms electric field strength (E, in V/m) or power density (S, in W/m 2 ) maximum  Paper presented at the 7 th International Balkan Workshop on Applied Physics, 5–7 July 2006, Constanþa, Romania. Rom. Journ. Phys., Vol. 52, Nos. 3– 4 , P. 429–440, Bucharest, 2007