Azimuthal scattering pattern of trees at X-band

The azimuthal scattering characteristics of a variety of fully foliated trees were measured in the field using a short-range X-band bistatic radar system operating at 9 GHz. Azimuthal measurements were made for both VV and VH polarizations over a 180 degrees angle between the transmitter and receiver antennas at 10 degrees intervals. Data were collected at transmit and receive ranges of approximately 5 m, and the beam impinged horizontally on the trees. The azimuthal power pattern, normalized to the copolarized backscattered power, showed a peak in the forward scattering direction (azimuth angle of 180 degrees ) due to direct coherent transmission, whose magnitude was seen to depend on the foliage area density. The diffuse bistatically scattered power in the range of azimuth angles between 10 degrees and 90 degrees showed standard deviations on the order of 4 dB. In addition, needleleaf trees were found to depolarize the incident energy more than the broadleaf trees.<
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