The perturbed cavity resonator under consideration is generated from a prismatic cavity with square cross-section by rotation of one of its walls through a small angle δ about its edge. The electric field vector is assumed to be everywhere parallel to that edge.
Part I deals with the fundamental vibration only. The change in resonance frequency and the distortion of the electromagnetic field due to the perturbation are calculated.
In Part II two fields, each with one nodal plane, are considered separately.
Part III deals with the case of two nodal planes perpendicular to each other.
In II and III the change in resonance frequency is calculated and special attention is paid to the distortion of the nodal planes.