Luminosity limitations at the multiTeV linear collider energy frontier

To achieve the desired high luminosity in e/sup +/e/sup -/ linear colliders with centre-of-mass energies above the TeV scale, careful optimisation of the beam parameters is necessary. Constraints arising from the RF structure design, the beam-beam interaction, the damping ring and the beam delivery system have to be taken into account and compromises between different requirements have to be found. The nature of these different constraints is discussed and the resulting limits for the luminosity are detailed. (24 refs).