Tham khảo tài liệu 'electromagnetic waves propagation in complex matter part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Electromagnetic Waves in Contaminated Soils 147 A yjJ 04 .85 Frequency GHz Fig. 14. Experimental frequency-response in water-saturated background soil cable and the bottom of the receiving antenna. Therefore it needs to be adjusted for this difference. Up to this point the FDTD travel-time t3 - t1 from the feed cable to the tip of the receiving antenna is computed. The travel time through the receiving antenna t4 - t3 which is by symmetry equal to t2 - ti should be added to t3 - t1 to find the total travel time between the feed and receiver cables t4 - ti for the FDTD model. The resulting travel time from the FDTD simulation can be used for comparison with the experimental results. The travel time computed from the forward model is 4500 900 - 1000 X 2 psec nsec which closely agrees with the one indirectly computed from the experimentally collected frequency-response data 5700 - 1000 X psec nsec. The difference is due to the slight potential discrepancy between the dielectric constant assigned to the forward model used from the results of another work by the authors Zhan et al. 2007 and the real values of the experimentation. The intensities of the unprocessed received signals from the FDTD simulation Fig. 13 a and experimentation Fig. 15 a agree relatively well but not perfectly. The reason is the potential slight discrepancy between the electrical conductivity assigned to the FDTD model compared to the actual one of the experiment. However due to the difference between the necessary processing methods different filters the intensity of the processed received signals for the FDTD simulation Fig. 13 b and the one of the experiment Fig. 15 b do not agree as closely. This comparison consists of the incident field for the homogeneous background soil. The comparison for the total and scattered fields at the presence of any anomalies . dielectric objects will be conducted in the future. .
