Research On Transmission Characteristics Of Inhomogeneous Dielectric Loaded Ridge Waveguide By The Finite Element Method

Due to a lower cutoff frequency, low impedance characteristics, wide single mode bandwidth and other advantages, ridged waveguide is more and more extensive in the application of microwave and millimeter wave device now, the research of ridged waveguide has not stopped, but the research of dielectric loaded ridge waveguide is little. In order to look for ridged waveguide devices which have better performance for the transmission in the engineering practice, all sorts of shapes of ridged waveguide and inhomogeneous dielectric loaded ridged waveguide need to be researched and analyzed, so as to design the fine waveguide devices.The transmission property of waveguide is one of the important targets to measure the performance.The cutoff characteristics, single mode bandwidth and attenuation characteristics are very important three aspects of the transmission characteristics, this thesis mainly studies the cutoff wavelength, single mode bandwidth and attenuation of inhomogeneous dielectric loaded rectangular, trapezoidal and inverted trapezoidal double ridge waveguide with the size of the ridged waveguide, the relative dielectric constant and working frequency change relations, these parameters values in horizontal waves mode are calculated and the charts of parameters change are drawn.The three parameters calculation formulas of inhomogeneous dielectric loaded ridged waveguide are derived from thery. By the finite element method and MATLAB software, the tnhornogeneous dielectric loaded ridge waveguides are modeled, programming to calculate the parameters with different sizes, the relative permittivity and frequency of inhomogeneous dielectric loaded ridge waveguides. Part of the data obtained is compared with the data of authoritative literature the method is verified to be feasible and correct.The research results show that the dielectric loaded ridge waveguide is easier to get longer cutoff wavelength and lower cutoff frequency than none dielectric loaded ridge waveguide; in the manufacturing process to the extent permitted, so as to get more wide single-mode bandwidth if make the distance between two ridges as far as possible. This type of ridged waveguide can be used for ridged waveguide filters, waveguide-type dielectric cylinder band-pass filter and amplifier, etc. The attenuation of homogeneous dielectric loaded ridge waveguide increases with the frequency decreases rapidly first and then tends to slowly increasing trend; when the operating frequency is fixed, the attenuation increases with the growth of the distance between two ridges or relative dielectric constant. In engineering practice, adjusting the thickness of dielectric in ridge waveguide according to the needs to achieve the minimum attenuation, thus reduce the energy loss in the waveguide. After the comparion of the data, it is obtained that inverted trapezoidal ridge waveguide has the biggest cutoff wavelength and single mode bandwidth. Inverted trapezoidal ridge waveguide is more conducive to miniaturization devices design of microwave. Attenuation has this order which is from small to big that trapezoidal, rectangular and inverted trapezoidal double ridge waveguide. So trapezoidal double ridge waveguide is more suitable for transmission of microwave information, rectangular ridge waveguide has smaller single mode bandwidth which makes it suits for the filtering system. The research results will enrich the existing data of dielectric loaded ridge waveguide, and provide evidence for the design and optimization of ridged waveguide.