The diffraction of a plane electromagnetic wave by two parallel, overlapping, perfectly conducting half-planes with a dielectric loading is considered by using the Fourier transform technique in conjunction with the mode-matching method. This mixed method of formulation enables one to obtain directly two uncoupled modified Wiener-Hopf equations instead of a matrix one. When the overlap length is set to zero and the dielectric loading is removed, the results are shown to coincide exactly with those obtained previously by Abrahams . Numerical results showing the effects of the dielectric loading on the transmitted field are also presented. (C) 2001 Elsevier Science B.V. All rights reserved.