Experimental Study of Dispersion/Attenuation by Trees from 1 to 40 GHz

With the aim of analyzing radiowave propagation in agriculture applications, this work presents experimental results regarding dispersion/attenuation caused when waves from 1 GHz to 40 GHz propagate through trees (bonsais). Depending on the position of the transmitter antenna, different dispersion patterns were measured. In this sense, the power delay profile (PDP) obtained with the presence of the tree is delayed and attenuated with respect to the PDP without the tree. Specifically, the tree dispersion/attenuation (TDA) due to the presence of the tree can be increased with frequency up to 9.8 dB. If the transmitter height is half the tree height, a difference of 7.4 dB has been observed in the maximum TDA. On the contrary, for a transmitter height double than the tree height, the difference is 2.2 dB.