Fourier-type spot-array illuminators are designed for electromagnetic fields in the paraxial domain of diffractive optics. An analytical construction of the periodic, spatially variable Jones matrix is presented, which produces 100% conversion efficiency from an arbitrarily polarized incident plane wave into M x N = 2(P) x 2(Q) (P and Q are integers) diffraction orders. Such perfect performance is not possible within the scalar theory of paraxial diffractive optics.