A shorted waveguide-stub coupling mechanism for narrow-band multimode coupled resonator filters
Date
2004
Authors
Steyn W.
Meyer P.
Journal Title
Journal ISSN
Volume Title
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Abstract
A shorted waveguide-stub coupling mechanism is presented for implementing narrow-band multimode coupled cavity filters without coupling screws. The coupling element is a shorted rectangular waveguide stub placed in the end walls of cylindrical filter cavities, using perturbation of the magnetic fields to obtain coupling between degenerate modes. This structure is well suited to analysis and design with the efficient and accurate mode-matching method. Coupling coefficients and resonator frequencies can be controlled by varying cavity dimensions and the length, width, and depth of the rectangular coupling element. The accuracy with which the coupling can be realized and the elimination of coupling screws reduce the amount of tuning substantially. A third-order Chebyshev filter, realized in a triple-mode cavity with no coupling screws and only two tuning screws, is presented to verify the use of the coupling structure.
Description
Keywords
Computer simulation, Finite element method, Insertion losses, Magnetic couplings, Natural frequencies, Rectangular waveguides, Tuning, Waveguide components, Cavity resonances, Coupling coefficients, Dual modes, Triple modes, Microwave filters
Citation
IEEE Transactions on Microwave Theory and Techniques
52
6
52
6