Study On Transmission Characteristics Of Partially Dielectric Loaded Ridge Waveguide With FDTD

Finite Difference Time Domain (FDTD) method was first promoted by Yee K.S. in1966and since then it has received widespread concern and has been widely used in the waveguide cavity system, the antenna radiation characteristics, electromagnetic compatibility and electromagnetic scattering.Due to the ridge waveguide has a longer cutoff wavelength and low impedance characteristics, it has widely used in the microwave and millimeter wave devices. Partially dielectric loaded ridge waveguides have important applications in practical engineering, compared to the non-filling dielectric ridge waveguide, it has longer cutoff wavelength and narrower single-mode bandwidth. However, researches on the characteristics of ridge waveguide are mainly focus on the non-filling dielectric ridge waveguide, the characteristics of dielectric ridge waveguide are rare, which to some extent, limit the analysis and design of ridged waveguide components. To solve this problem, we have studied the transmission characteristics of partially dielectric loaded ridge waveguides with FDTD method.FDTD method is wildly used in the computational electromagnetics. In this thesis, the TE mode’s transmission characters of rectangular, trapezoidal and inverted trapezoidal dielectric loaded symmetrical double ridge waveguide have been calculated on the basis of the principles and its related technologies of the FDTD method, combined with MATLAB software tool for modeling the dielectric ridge waveguide. Part of the data obtained is compared with the data of authoritative literature. As the error is in a reasonable range, so the method is verified to be feasible and correct.The thesis systematically studied the cutoff wavelength, single-mode bandwidth and attenuation of partially dielectric loaded ridge waveguide, and the relationship with the dielectric constant and dimensions of the ridge waveguide, and gives the calculated data and the curve. The results show that the transmission characteristics of partially dielectric ridge waveguide have a certain relationship with the structure parameters and relative dielectric constant of the medium. The dielectric loaded ridge waveguide is easier to get longer cutoff wavelength and lower cut-off frequency than none dielectric loaded ridge waveguide. In the manufacturing process to the extent permitted, we can adjust the thickness of media in ridge waveguide according to the needs to achieve the minimum attenuation. By comparing the data we can see that inverted trapezoid ridge waveguide has the biggest cutoff wavelength and single-mode bandwidth, it is more conducive to miniaturization devices design of microwave. Rectangular ridge waveguide has the smallest single-mode bandwidth which makes it suits for the filtering system. Trapezoid double ridge waveguide is more suitable for transmission of microwave information. The results in this thesis will enrich existing data for dielectric ridge waveguide, and helpful in the design and engineering applications of the ridge waveguide.