Electromagnetic fields in cavities containing scattering objects

Formulas describing the electromagnetic field in a rectangular cavity are derived from the Lorentz potential function. These formulas describe the incident field excited by an electric current filament arbitrarily located in the cavity. From these formulas, approximations are obtained for the diffracted field caused by current induced on the surfaces of scattering objects. The total field is then the sum of the incident and diffracted fields. Results of calculations for a shield room with a conducting work bench are shown. These examples show the changes in the field strength with changes in either the frequency or antenna position.