  We report on an experimental platform based on an atom chip encompassing a
coplanar waveguide which enables to manipulate a quantum gas of sodium atoms
with strong microwave fields. We describe the production with this setup of a
very elongated degenerate quantum gas with typically 10^6 atoms, that can be
prepared all along the cross-over from the three-dimensional to the
one-dimensional regime depending on the atom number and trapping geometry.
Using the microwave field radiated by the waveguide, we drive Rabi oscillations
between the hyperfine ground states, with the atoms trapped at various
distances from the waveguide. At the closest position explored, the field
amplitude exceeds 5 G, corresponding to a Rabi frequency larger than 6 MHz.
This enables fast manipulation of the atomic internal state.
