Completeness and orthogonality of the null plane of one class of solutions of the relativistic wave equations

Possible redefinitions of the scalar product are analyzed for relativistic wave fields of the Klein-Gordon and Dirac types. It is shown that for an entire class of new exact solutions, for which it was previously not possible to define the usual scalar product on the x⁰=const plane, it is possible to find a correct scalar product on the null plane x⁰?x³=const. Orthogonality and completeness relations are proved for this scalar product. Possible applications of the results are discussed.