Scattering Effects of Residential Trees on Very Hugh Frequency Radio Wave Propagation

Abstract

Modeling of attenuation of Very High Frequency radio signal in residential environment can be very tedious as the channels are rarely characterized by vegetation of the same variety. This work focus on path loss measurement and attenuation modeling of the coherent scattered field intensity of VHF as it propagates through Mango and Jathropha trees. The two separate trees were illuminated uniformly with 2.15dBi dipole antenna connected to 60W transmitter while 1.7dBi short dipole connected to GSP-730 Spectrum Analyzer was used for reception. Path loss due to each canopy were estimated relative to the scattering angles. Dry-matter fraction of the leave were determined using sensitive weigh balance and corresponding effective dielectric properties of the leaves and branches peculiar to each tree were estimated using semi-empirical formula. Specific attenuation models were developed separately for the two trees relative to dielectric properties of each tree leaves and branches. The results show that path loss due to single Mango tree canopy ranges from 100dB to 140dB and that of Jathropha ranges from 95dB to 135dB. The results also show that total specific attenuation of the two trees depends on frequency, wavelength and dielectric properties of the canopies constituents