NUMERICAL-ANALYSIS OF CAPACITIVE DISCONTINUITIES OF FINITE THICKNESS IN RECTANGULAR WAVE-GUIDES USING THE MODIFIED RESIDUE-CALCULUS METHOD

The problem of electromagnetic scattering by capacitive discontinuitie s located in rectangular waveguides, in particular when dealing with d iscontinuous conductors of finite thickness, is analyzed using the mod ified residue-calculus method, and form of the equation suitable for a numerical calculation is derived. The incident wave is taken to be th e dominant mode, and reflection and transmission properties of an asym metric capacitive iris are discussed. After the modal representation o f the filed, the modal matching is apply to satisfy the boundary condi tions at the discontinuity. And using the modified residue calculus me thod, simultaneous infinite equations, which are concerned with the sc attered mode coefficients, are derived. Then they are approximated at the thick diaphragm. The solutions obtained take on the form of an inf inite product, and a numerical solution based on the method of success ive approximations is presented as a technique for concretely determin ing the reflection coefficients. As confirmation, experiments are also carried out in the X-band and close agreement is shown between the ca lculated and experimental values.