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By changing only the values of the spot size from w<sup>0</sup> = 0.15 mm, w<sup>0</sup> = 0.2 mm, and w<sup>0</sup> = 0.25 mm to w<sup>0</sup> = 0.26 mm, w<sup>0</sup> = 0.28 mm, and w<sup>0</sup> = 0.3 mm, respectively, the results of the output power density for a = 0.5 mm are changed as shown in

The output modal profile is greatly affected by the parameters of the spot size and the dimensions of the cross section of the waveguide. Figure 10(a)–(c) demonstrates that in addition to the main propagation mode, several other secondary modes and symmetric output shape appear in the results of the output power density for the

The proposed technique in Section 4.2 is also effective to solve discontinuous problems of the straight hollow circular waveguide with three dielectric layers

Several examples for the rectangular and circular waveguides with the discontinuous dielectric profile in the cross section of the straight waveguide were dem-

Figure 5(a)–(e) demonstrates the output field as a response to a half-sine (TE10) input-wave profile in the case of the rectangular dielectric profile in the rectangular waveguide (Figure 1(b)), where a = b = 20 mm and c = d = 2 mm, for ε<sup>r</sup> = 3, 5, 7, and 10, respectively. By increasing only the dielectric profile from ε<sup>r</sup> = 3 to ε<sup>r</sup> = 5, the width of the output field increased, and also the output amplitude increased. The output fields are strongly affected by the input-wave profile (TE<sup>10</sup> mode), the location, and the dielectric profile, as shown in Figure 4(a)–(c) and Figure 5(a)–(e). The behavior of the output fields (Figures 5(a)–(e) and 6(a)–(e)) is similar when the dimensions of the rectangular dielectric profile (Figure 1(b)) and the circular profile (Figure 1(c)) are very close. The output field (Figure 5(a)–(e)) is shown for c = d = 2 mm as regards to the dimensions a = b = 20 mm. The output field (Figure 6(a)–(e)) is shown where the radius of circular profile is equal to 1 mm

Figures 6(a)–(e) and 7(a)–(e) show the output field as a response to a half-sine (TE10) input-wave profile in the case of the circular dielectric profile (Figure 1(c)), for ε<sup>r</sup> = 3, 5, 7, and 10, respectively, where a = b = 20 mm, and the radius of the circular dielectric profile is equal to 1 mm. By changing only the value of the radius of the circular dielectric profile (Figure 1(c)) from 1 mm to 2 mm, as regards to the dimensions of the cross section of the waveguide (a = b = 20 mm), the output field of the Gaussian shape increased, and the half-sine (TE10) input-wave profile

Figure 8(a)–(c) shows the output field as a response to a half-sine (TE10) inputwave profile in the case of the hollow rectangular waveguide with one dielectric material between the hollow rectangle and the metal (Figure 1(e)), where a = b = 20 mm, c = d = 14 mm, and d = 14 mm, namely, e = 3 mm and f = 3 mm. Figures 9(a)–(c) and 10(a)–(c) show the output power density in the case of the hollow circular waveguide with one dielectric coating (Figure 1(f)), where a = 0.5 mm. By changing only the values of the spot size from w<sup>0</sup> = 0.15 mm, w<sup>0</sup> = 0.2 mm, and w<sup>0</sup> = 0.25 to w<sup>0</sup> = 0.26 mm, w<sup>0</sup> = 0.28 mm, and w<sup>0</sup> = 0.3 mm,

Figure 4(a)–(c) demonstrates the output field as a response to a half-sine (TE10) input-wave profile in the case of the slab profile (Figure 1(a)), where a = b = 20 mm, c = 20 mm, and d = 2 mm for ε<sup>r</sup> = 3 and 5, respectively. By increasing only the value of the dielectric profile from ε<sup>r</sup> = 3 to ε<sup>r</sup> = 5, the width of the output

values of w<sup>0</sup> = 0.26 mm, w<sup>0</sup> = 0.28 mm, and w<sup>0</sup> = 0.3 mm, respectively.

(Figure 1(g)), and some examples were demonstrated in Ref. [21].

onstrated in this research, according to Figure 1(a)–(g).

field decreased, and also the output amplitude decreased.

(viz., the diameter 2 mm), as regards to the dimensions a = b = 20 mm.

Figure 10(a)–10(c).

Electromagnetic Materials and Devices

6. Conclusions

decreased.

64

Zion Menachem Department of Electrical Engineering, Sami Shamoon College of Engineering, Beer Sheva, Israel

\*Address all correspondence to: zionm@post.tau.ac.il

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
