The present thesis deals with the electromagnetic modeling, design and practical implementation of a planar antenna for the reception of satellite broadcasting services from user terminals on board automotive platforms. This antenna is intended to address the market of low cost consumer applications. As a consequence, stringent structural and performance-to-price ratio requirements have to be imposed. The antenna has been conceived as a low profile phased array, on a multilayer planar technology, with fully electronic beam steering and polarization tracking capabilities. The success of this approach strongly relies on the ability of designing highly sophisticated planar multilayered radiators that will act as array elements providing both adequate performance and enough geometrical flexibility to match the constraints dictated by the imposed array topology and structure. The main subject of this thesis is the basic building block of such an antenna, the so-called Elementary Radiating Cell. This cell not only comprises the bare radiators but also the passive circuits (hybrids, power combiners, long via-holes through the multilayered substrates) able to connect the radiating elements to the array beamforming feeding network. The implementation of this Elementary Radiating Cell must be compatible with the available multilayer technologies and with the selected array lattice. This severely limits the available volume and poses some trade-off problems, whose solution has been one of the most challenging efforts in this thesis. This thesis has been carried out in the framework of a joint project between the European Space Agency, several key industrial partners in the sector of satellite R&D and consumer applications, led by IMST-Germany, and the EPFL Laboratoire d'électromagnétisme et d'Acoustique (EPFL-LEMA). The project has demonstrated the feasibility of the electronically steered phased array antenna concept in the development of a new generation of compact satellite terminals for the automotive market.