Te Mode And Tm Mode Dual-mode Waveguide Filter Is Developed

This paper designed the TE dual-mode waveguide filter and the TM dual-modewaveguide filter. It is based on the field structure of the mode, which propagates theelectromagnetic wave in the rectangular waveguide. The resonance modes in the TEcavity are the TE101and the TE011. The resonance modes in the TM cavity are the TM₁₂₀and the TM₂₁₀. The resonance frequencies of the two modes are independent ofthickness according to the calculation formula of the resonant wave. Because of this, theTM dual-mode waveguide filters can achieve a very compact structure.Firstly, the field component in the rectangular waveguide which belongs toeigenvalue problem was solved by the use of the classic Maxwell’s equations in thecombination with the boundary conditions of a rectangular waveguide. Next, the fieldstructure of the often used mode and the degenerate mode in a single rectangularwaveguide were discussed.Additionally, the generalized Chebyshev filter matrix synthesis theory wasintroduced, which was used in the design of TE dual-mode waveguide filters.Thirdly, three different kinds of coupling structure were described in the design ofdual-mode waveguide filter, but also the modified coupling matrix, which clearlyexplain the coupling between modes in a single cavity. Finally, a two cavity fourthorder TE dual-mode filter was designed by exploiting capacitance loading technology,the filter realized two symmetric transmission zeros.Finally, based on the design method of the waveguide filter using the TM110mode,the paper did a research on TM dual-mode waveguide filter, and then detailedlyanalyzed and discussed the parameters controlling the transmission zeros position andthe bandwidth. At last, a design example of fourth order TM dual-mode waveguidefilter with two pairs of symmetrical transmission zeros was given.