Circuit theory approach to shielding

There are two approved methods for approximating the shielding effectiveness of shielding m,aterials used in the design of shielded enclosures and boxes. Both of the approved methods use wave theory and quasi-stationary assumptions. One of the methods uses Maxwell??s equations to estimate the shielding, and the other uses the correlation between transmissiain lines and radiated waves. A third method consisiting of circuit theory (or Kirkoff´s Law) is proposed herein as an applicable method of approximation worthy of consideration.