Incremental length diffraction coefficients (ILDC) is often used to calculate the diffraction by edges.However

ILDC displays infinities for certain combinations of observation and incidence directions.To eliminate such infinities

Michaeli derived a set of expressions for the fringe current components of equivalent edge currents

those expressions are finite for all aspects of illumination and observation

except for the Ufimtsev singularity.However

for certain non-singular aspects of ILDC

maybe there is a wide divergence between these two methods' results.In this paper

new exppressions for fringe current components of equivalent edge currents are presented.Compared with those given by Michaeli

new expressions can not only eliminate the infinities in LDC effectively

but also keep good agreement with ILDC.So it is very valuable in practical applications.