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U ovom su radu opisane karakteristike antena, podjela antena i parametri antene. Objašnjeni su mehanizmi propagacije radiovalova: ogib refleksija, refrakcija, disperzija i apsorbcija. Dan je pregled modela propagacije radiovalova koji predviđaju jakosti polja u različitim uvjetima. Provedena su mjerenja jakosti polja sinusnog signala na 900 MHz u unutarnjem prostoru u zgradi Elektrotehničkog fakulteta u Osijeku. Izmjerene su jakosti polja u hodnicima u uvjetima optičke vidljivosti te u prostorijama s jednim ili više zidova između odašiljača i antene. Izmjereni rezultati su uspoređeni sa vrijednostima izračunatima prema modelu propagacije u slobodnom prostoru. This paper describes the characteristics of the antenna, the classification of the antennas and the antenna parameters. It explains the mechanism of radio waves propagation: diffraction reflection, refraction, dispersion and absorption. An overview of the propagation models of radio waves which predict the field strength in a variety of conditions is given. Field strength of a sinusoidal signal at 900 MHz in the interior of the building in the Faculty of Electrical Engineering is measured. Field strength is measured in the corridors in conditions of optical visibility as well as in the rooms with one or more walls between the transmitter and the antenna. The measured results are compared with the values calculated by the model of propagation in free space.