Full Wave Derivation of Equivalent Circuit for Waveguide Dielectric Resonator Filter

A full wave algorithm. is proposed to derive an equivalent circuit suitable for the design of rectangular waveguide filters employing cylindrical dielectric resonators in TE
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mode. Two basic structure are considered: the input/output step and a section of evanescent waveguide, both including half a dielectric resonator. The corresponding models are extracted by proper FIT analyses, all performed at the central frequency only, and include also the frequency derivative of equivalent parameters. These derivatives are in particular evaluated as a by-product of field analyses by Foster's reactance theorem. Chaining and manipulating the basic equivalent circuits, an accurate and effective design of this class of filters is made possible.