Ultrawide Band Backscattering Measurement of Tree at Ka Band
In this paper, we present Ka‐band backscattering measurements of banyan and pine trees on NCU campus. Thecoherent radar system, designed and configured based on a vector network analyzer N5245A PNA‐X (10MHz‐50GHz) is capable of measuring the return power from 26.5 GHz to 40GHz for VV, HH, VH polarizations at incidenceangles between 20 and 80 degrees. In measuring process, the radar system has typical trace of the frequencyranges from 26 to 33GHz and 34GHz to 40GHz of the received power for a given footprint of tree canopy. For thisultrawide bandwidth, the wind‐induced Doppler effects can be ignored. Undesired returns from outside theantenna beam volume are conveniently rejected by gating in time domain. By this feature, the propagating depththrough the tree can also be precisely determined so that the effective propagation constant and attenuationfactor can be estimated. A reference measurement was taken at normal incidence using a conducting sphere as acalibration target. The calibration was conducted both in anechoic chamber and in‐situ measurements. Ensembleaverage well over 1000 samples were taken to estimate the mean return power and later by inverting the radarequation to obtain the backscattering coefficient as functions of frequencies (26GHz to 40GHz) and incidentangles are then estimated. To simplify the matrix inversion, a narrow beam is realized with dish antenna. Basedon the measured results, backscattering characteristics and statistical properties were analyzed for the cases ofdeciduous (banyan) and coniferous (pine)trees.
Backscattering coefficient Anechoic chamber.
Wei‐An Chuang Kun‐Shan Chen Chih‐Yuan Chu J. C. Shi
Institute of Space Science Institute of Space Science Center for Space and Remote Sensing National Central University, Chung‐Li Center for Space and Remote Sensing National Central University, Chung‐Li 32054, Taiwan ICESS, University of California at Santa Barbara Santa Barbara, CA 93117 USA
国内会议
哈尔滨
英文
1-4
2011-08-01（万方平台首次上网日期，不代表论文的发表时间）