Time-domain electromagnetic penetration through arbitrarily shaped narrow slots in conducting screens

A time-domain integral equation is derived for the unknown electric field, or equivalent magnetic surface current, in a narrow slot in a conducting surface, and an efficient and stable numerical method is developed for solving this equation. The contour of the slot in the vanishingly thin conducting surface may be of any shape. The solutions are compared via Fourier transformation with those of the corresponding time-harmonic integral equation, and they are further validated by demonstrating close correlation between values of the calculated field on the shadow side of the conductor and data from laboratory measurements. For numerous slot lengths and shapes, time- and frequency-domain data illustrating the behavior of the slot field and penetrated field are presented and compared with measured results. The stability of the time-domain solution technique is investigated and found to be very high. The response of a slot to an EMP-type (electromagnetic pulse type) pulse is presented as an example