The problem of diffraction by perfectly conducting plane complementary sectors assumes canonical form when conical geometry is used. This allows us to express the diffracted fields like spectra of E and H -modes and to unify the two problems simply invoking complementary limit conditions in the Sturm-Liouville problems for the pertaining Debye potentials. In particular, from the unification properties relative to the fundamental E and H modes it follows that the electric/magnetic singular behaviours by the tip conductor are identical to the magnetic/electric singular behaviours by the complementary tip conductor. For utility in printed circuit analysis, the former singular behaviours are formulated as simple weighting functions and the problem of EM singularities excitation along the conductor edge of any printed circuit is discussed.