Journal of Information Engineering and Applications www.iiste.org ISSN 2224-5782 (print) ISSN 2225-0506 (online) Vol.3, No.7, 2013 11 UHF band Radio Wave Propagation Mechanism in Forested Environments for Wireless Communication Systems Ayekomilogbon Olufemi 1 , Famoriji Oluwole 2* and Olasoji Olajide 3 1. Engineering Department, Ondo State Radiovision Corporation, P. O. Box. 1336, Akure, Nigeria. 2 and 3. Department of Electrical and Electronics Engineering, Federal University of Technology, P.M.B.704, Akure, Nigeria * E-mail of the corresponding author: famorijijohn@yahoo.co.uk Abstract Radio frequency propagation is the mechanism of the transfer of energy or information at radio frequencies from one point, a transmitter, to another, a receiver. The energy radiated by a transmitter may take several paths before it is received. The path to be taken by radio wave depends on certain factors, such as: frequency, antenna type and height, atmospheric conditions and terrain. In this research work, UHF broadcast signal strength measurements were taken for both wet season (trees in leafs) and dry season (trees relatively out of leaf) in Akure-Ilara route of Ondo state, Nigeria and the result obtained were validated against the theoretical estimations. However, in the wet season, there were more attenuation of signal compared to dry season and signal degradation is a function of leaf density. The lower the leaf density, the better the signal received. It is thereby required, in wet season more power is expected to be pumped out from the transmitter in order to cover the targeted areas. Keywords: Radio wave, Forest, Measurements, Signal strength, UHF, Akure-Ilara 1. Introduction Achieving optimal performance is a paramount concern in wireless networks [1]. The appearance of the foliage medium in the path of the communication link as presented in Fig. 1 has found to play a significant role on the quality of service (QoS) for wireless communications over many years [2]. Discrete scatterers: the randomly distributed leaves, twigs, branches and tree trunks can cause attenuation, scattering, diffraction, and absorption of the radiated waves. This will severely constrain the design of modern wireless communication systems. Wireless communication is Figure 1: Radio wave Propagation Mechanism affected by many environmental factors not foreseen by developers, not accounted for by simulators, and not considered by theoretical models [3, 4]. This is especially true for an arable farming environment in which growing crops (foliage) and ever-changing weather conditions have an unknown effect on the exact propagation of the radio waves. Since the year 1960s, a significant amount of work has been done to investigate the radio wave propagation in forested environment. Analytical and empirical works on the modeling and characterization of the forested channel have been carried out. Some useful and significant results and analysis are reported in [5]. It is reported that the foliage medium can attenuate the propagating radio wave significantly. There are many external factors that will cause the variation in radio wave propagation and even the complete breakdown of communication link