1998 Volume 63 Issue 514 Pages 57-61
In this paper, an approximate equation to represent the relationship between the size of an opening in a far field and shielding effectiveness and an equation to represent the relationship between frequency and shielding effectiveness were developed using the theoretical equation of an evenly distributed opening surface antenna. The insertion loss method was used as a prerequisite for this approximate equation. The formula of an approximate equation is based on the far field, but comparison with the experiment data obtained on a nearfield (electric field and magnetic field) basis revealed that the equation is also applicable to the near field. The following equation that generalizes the coefficients of the approximate expression was therefore obtained. I propose that this equation be used as prediction standard equation. S = A long(a)+B log(b)+C a: height of an opening (m) b: width of an opening (m) A, B, C: constant at each electromagnetic field; but in the case of a far field they are frequency logarithmic functions.
