Research On Loss Characteristics Of Ridge Waveguide By Finite Element Method

Since Cohn obtained the relevant characteristics parameters of rectangular ridge waveguide using analytical method in his paper, ridge waveguide has received considerable attention and been widly used in microwave engineering, space technology,wireless communications, electronic warfare, electromagnetic compatibility and other fields because of wide single-mode brandwidth, low cutoff wavelength and small characteristic impedance.Loss characteristics are important parameters to choice and design the ridge waveguide. However, the research and calculation data of loss characteristics are few, which makes the applications of ridge waveguide are limited. Therefore, calculation and analysis of the loss characteristics of ridge waveguide is valuable in engineering.Based on finite element method, under the MATLAB environment, programming is realized to perform triangular element gridding to the cross-section of ridge waveguide and calculate the loss characteristics. Parameters of the ridge waveguide under different structure in the main mode transmission are calculated. Paper presents the data and curves of loss characteristics for rectangular, trapezoidal, inverted trapezoidal, triangular single-ridged and double-ridged waveguide when structure dimensions and working frequence change. Calculated data agree well with the literature published on authoritative papers, which proves that the method used in this paper is feasiby and correct.Based on introduction of the basic theory of waveguide and finite element method, the practical significance of the research is described in this paper. The results show that loss characteristics of ridge waveguide are related to structure parameters and working frequency. As the working frequency f increases, the normalized attenuation constant monotonically decreases.Amplitude is large when operation frequency is bigger than (?) times of the cutoff frequency, but small when operation frequency is smaller than (?) times of the cutoff frequency. When the operation frequency is fixed, attenuation constant decreases as the distance between the ridges d increases, power-handling capability increasesas d increases.After the comparison of the data of loss characteristics for various shapes of ridge waveguide, it is found that trapezoidal and inverted-trapezoidal ridge waveguide is suitable for microwave information transmission because of small attenuation constant and large power-handling capability. Triangular ridge waveguide has large attenuation constant and small single-mode bandwidth which makes it suits for the filtering system. It is shown that the loss characteristics of symmetrical double ridge waveguide are better than single ridge waveguide with the same proportion after the comparision of the data. The obtained data of loss characteristics can support the applications of ridge waveguide devices in engineering. The conclusions are considered to be helpful in design and potential applications of ridge waveguide devices.