Resonant electromagnetic field coupled into a lossy cavity through a slot aperture

A new approach is proposed for determining the electromagnetic fields coupled from an incident plane wave into a lossy conducting cavity through a slot aperture under resonant conditions. Use is made of the duality between a slot and a conducting strip and of the equivalence between a strip and a wire. Simplified formulas are derived that are explicit and flexible. Determination of resonant fields inside a cavity is reduced to simple calculations. Numerical examples are given.