EHF propagation through foliage

An EHF experiment was performed in which a 30-foot maple tree was placed between a 2-foot parabolic antenna and a distant transmitting site operating at 20 and 44 GHz. The objective was to measure attenuation through foliage. Results indicate that attenuation is nearly the same at the two frequencies. A value of 4 dB/meter can be used as a rough guide for deciduous trees in full leaf. Measurements on single maple leaves and pine needle clusters plus a study of the literature tended to reinforce the conclusions of the tree experiment, and to show that evergreen trees can be expected to have similar attenuation values.