This paper presents a new design of a planar solar concentrator for space applications. The concentrator focuses light onto two spatially separated photovoltaic cells, allowing for independent control of the output power of each cell. Thanks to a blazed diffraction grating superimposed on a Fresnel lens, advantages of both spectral splitting and light focusing can be combined. The theoretical model of the optical design is presented, with the optimization of either element. Moreover, configuration improvement is proposed: a symmetrical configuration composed of two lenses. First numerical results are presented, highlighting the possibility to design a concentrator at about 10 x for each cell, with an optical efficiency of about 75% and less than 10% of losses for tracking errors lower than +/- 0.9 degrees (C) 2013 Elsevier B.V. All rights reserved.