By Topic

Modeling ordered trunks at VHF with an effective description

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
W. M. Merrill ; Sensor-com, Sanba Monica, CA, USA ; N. G. Alexopoulos

Below VHF frequencies a forest may be accurately represented with an anisotropic effective permittivity that accounts for the average field within the foliage. At higher frequencies however, a quasi-static representation is no longer valid and coherent interaction of the scattered field must be accounted for. This paper provides an effective representation of a forest, which accounts for the zeroth harmonic interaction of the scattered field off the trunks. This is accomplished by assuming an ordered distribution of tree trunks, and when combined with a quasi-static description of the canopy (perturbed to provide a first order account of scattering) to create a propagation model of an orchard, valid up to UHF frequencies. To create an effective representation of tree trunks applicable beyond the quasi-static limit an effective representation based on a transfer matrix description is applied to an ordered array of cylinders. The ordered array of tree trunks, rather than a disordered forest is considered as this may be treated more easily and provides the most violently dispersive response. To account for the branches off the trunks a Lindenmayer algorithm may then be used to numerically simulate the branch density as a function of height, and from that an effective permittivity is determined based on the branch density and connectivity. Within this paper, specifically an ordered array of tree trunks is considered with size and spacing consistent with eastern white pines.

Published in:

Antennas and Propagation Society International Symposium, 2000. IEEE  (Volume:4 )

Date of Conference:

16-21 July 2000