A detailed calculation of energy-band structures and dispersion relation of compensated n-i-p-i superlattices with small period lengths is presented. The calculation is based on a multistep-function approach to the real potential form and the transfer-matrix method. The densities of states of conduction subbands have been calculated. We found that the density of states is different for different subbands. Some special features of small-period doping superlattices have been explored, and are compared with properties of long-period n-i-p-i compensated doping superlattices as well as GaAs-AlxGa1-xAs compositional superlattices.