Fields in slanted-gap excited rectangular ducts

Some features of the electromagnetic field in a rectangular wave-guide, cut in two by a plane making an angle θ with the guide's longitudinal axis, are examined. The field is excited by a voltage applied across the two halves of the guide. Several values of θ, frequency (between zero and cut-off), and aspect ratio of the cross-section are considered. The problem is of interest for the design of particle accelerators, and, with this particular application in mind, data are presented for the energy and momentum kicks which particles experience when crossing the gap.