In this paper

the generalized impedance transformation method[1] is used to solve eigenequation and eigenvalue of the fundamental mode in the specific waveguide with various shapes. This method reduces the engineering calculation to solving the general epuation. It’s conciseness is very obvious especially for dealing with complex problems. Several typical examples are computed and experimented. The results of the computation are basically identical with those of references[2

3

4]. The specific waveguides have found many applications in microwave power sources and microwave magnetic devices. There have been a number of methods for analysing and treating this kind of waveguides. But up to now

no concise and general methods is reported for dealing with various shape waveguides. The introduction of unconti nuous capacitances and the change of matrix elements which change with the variation of transverse impedances are considered

and by using the generalized impedances transformation method

the eigenequation which is

to a certain extent

general for various shape waveguides is derived. This method described can meet the requirements for engineering calculation.