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Behaviour of Electromagnetic Waves in Different Media and Structures Part 3

Tham khảo tài liệu 'behaviour of electromagnetic waves in different media and structures part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 48 Behaviour of Electromagnetic Waves in Different Media and Structures plane H wave 5 5.5 6 6.5 7 7.5 8 8.5 f GHz k Fig. 24. Power reflection coefficients of the fundamental space harmonics versus frequency for normal incidence of TE wave on a periodic structures Parameters of the structures h 20mm l h r 0.06h R 0.35h r1 3 r2 2.5 number of sections 20. f GHz plane structure 1 structure 2 Fig. 25. Schematic 3-D representation of a periodic structure under investigation Fig. 26 illustrates the power reflection coefficients for the normal incidence of a TE polarized plane wave on stacks of periodic structures of dielectric cylinders with double dielectric inclusions. The characteristics for scattering from structure 1 2 and 3 are illustrated. The results show that stacks 1 and 2 are completely opaque in presented frequency ranges. However when half of these configurations are rotated by 90 with respect to the other half forming the structure 3 the tunneling effect can be observed. The obtained configurations enable the signal from a very narrow frequency range to tunnel through the structure. This tunneling effect can be controlled by adjusting the distance d between stacks see Fig. 25 . Fig. 27 shows the characteristics of the power reflection coefficients for the normal incidence of a TE polarized plane wave on structure 3 for different values of distance d. It can be clearly seen that this value is directly connected to the frequency of the tunneled wave. Electromagnetic Wave Scattering from Material Objects Using Hybrid Methods 49 plane k ------structure 1 single unit cell plane Fig. 26. Power reflection coefficients of the fundamental space harmonics versus frequency for normal incidence of TE wave on a periodic structures Parameters of the structures h 20mm I 20mm d l R 0.48h r 1.5 inclusion - two dielectric cylinders r 0.16h rc 2 displacement from the center .24h number of sections 20 d 1.4l Fig. 27. Power reflection coefficients of the fundamental space .