Resonant Transmission of an Electrically Small Aperture with a Ridge

A resonant transmission of an electrically small aperture with a ridge in a conducting plane is analyzed. It is an example of resonant transmission and the ridge inserted at the center line of the electrically small aperture resonates it by increasing an equivalent capacitance of the aperture. At resonance condition, the transmitted power through the aperture can be significantly enhanced compared to that at off-resonance. It is found that the transmitted power at the resonance condition converges to the transmission cross section of the aperture regardless of its size or shape. In addition, the electric and the magnetic fields distributions on the aperture with and without the ridge are compared to facilitate the understanding of the resonant behavior.