  The globalised cascaded scattering matrix technique is a well proven,
practical method that can be used to simulate large accelerating RF structures
in which realistic fabrication errors to be incorporated in an efficient manner
without the necessity to re-mesh the entire geometry. The globalised scattering
matrix (GMS) technique allows one to obtain the scattering matrix for a
structure. The method allows rapid e.m. field calculations to be obtained.
Results are presented on monopole mode fields and dispersion relations
calculated from direct and analytical methods. Analytical approximate results
are also presented for the equivalent shunt susceptance of an iris loaded
structure.
