Earth-satellite tree attenuation at 20 GHz: foliage effects

Static tree attenuation measurements at 20 GHz (K-band) on a 30° slant path through a mature Pecan tree with and without leaves have shown median fades exceeding ∼ 23 and 7 dB, respectively. The corresponding 1 % probability fades were 43 and 25 dB. Previous 1.6 GHz (L-band) measurements for the bare tree case showed fades larger than those at K-band by 3.4 dB for the median and smaller by ∼ 7 dB at the 1% probability. Although the presence of foliage had only a small effect on fading at L-band (∼ 1 dB additional for the median to 1% probability range), the attenuation increase was significant at K-band, where it increased by ∼ 17 dB over the same probability range.