Five-element spatial power divider/combiners have been realized at 150 GHz. Holography is applied to couple the field pattern of an in-line rectangular horn antenna array to a pseudo-plane wave. The hologram is realized as periodic phase grating. The transformation of the pseudoplane wave to a Gaussian beam is performed by phase modulation with a dual-offset reflector on the one hand, and a system of Fresnel lenses on the other hand. Both setups have been extensively examined. The analysis has been enhanced by a vector near-field measurement system. The comparison of the simulated and measured efficiencies, as well as field distributions shows good agreement.