The aim of this paper is to determine the dielectric characteristics of tropical wood species at microwaves frequency in order to use them as planar antenna substrate. The measurements have been done on dried wood in the frequency range 8.2-12.4 GHz The suitability of wood as a microwave printed antenna substrate will be determined by the values taken by the complex parameters "permittivity" epsilon and "permeability" mu and the loss tangent tan delta. The measurement methods were based on the waveguide method and the open resonator technique The first method gave us the reference values while the second one confirmed the previous measurements. Values obtained in the three principal axis of each species confirm the anisotropic nature of wood. These measurements will also confirm that the losses which are the main criteria of selecting wood as substrate grow with the density of the wood. (C) 2009 Elsevier Ltd. All rights reserved