Fast estimation of shielding efficiency of cavity with thin slots

A fast semi-empirical and semi-analytical method for shielding efficiency (or coupling efficiency) estimation of slot with large length-width ratio is presented. The method is based on coupling theory of small holes and Green’s functions of rectangular cavity excited by magnetic current. The result of the method matches well with that obtained by Micro-Stripes software and the measured result. The relationship between slot position, slot number, cavity volume and the shielding efficiency is analyzed. Calculation result shows that the shielding efficiency will degrade by 6 dB when adding a similar slot, and that when keeping slot length unchanged, shielding efficiency will increase by 1 dB when the length-width radio is two times larger and that the shielding efficiency will rise when the