  We report transport measurements on a Si/SiGe quantum dot subject to
microwave excitation via an on-chip antenna. The response shows signatures of
photon-assisted tunneling and only a small effect on charge stability. We also
explore the use of a d.c. current applied to the antenna for generating
tunable, local magnetic field gradients and put bounds on the achievable field
gradients, limited by heating of the reservoirs.
