  The design of future circular high-energy hadron colliders is based on the
achievement of challenging magnetic fields, needed to keep the hadron beams
orbiting along the ring circumference. The strength of the dipolar magnetic
field is a function of the machine radius, beam energy, and of the fraction of
the ring circumference that can be filled with dipoles. In this paper we
propose to use a combined-function periodic cell to maximise the filling factor
of the dipole magnets. The optical properties of the proposed periodic
structure are discussed in detail together with the design of the
superconducting magnets needed to implement the proposed approach.
