A Study on Characteristics of Electromagnetic Waves Propagating Through the Space Between Overlapped Metal Plates

The characteristics of electromagnetic (EM) waves propagating through the space between overlapped metal (conductive) plates and electrically conductive parts, which usually exists around a metal shielded box, are discussed in this study. The authors developed a method for measuring the current density distribution on the interface between the overlapped and energized metal plates. Using this method, the authors estimated that the general area of the electrically conductive parts is less than about 10 × 10 mm². Thus, the space between overlapped metal plates and electrically conductive parts is frequently expected to be extremely thin for the width and short in the direction of EM wave propagation. In this case, it was confirmed that the extremely thin and short space can be regarded as a rectangular waveguide for the propagation of EM waves.