In two previous papers [1,2] the emission current from a sandwich cathode was calculated under various assumptions about the properties of the dielectric layer. The angular distribution of electrons emitted from this cathode is calculated in the present paper. The derived characteristics for the case of ideal dielectrics, dielectrics with phonons and traps are then compared with the experimental results from papers [3–5] and some conclusions are drawn about the dielectric layer. It is shown that isotropic angular distribution requires extraordinarily short mean free paths for elastic interactions (equal to several Å) and large mean free paths for collisions with traps (at least larger than several tens Å).