  We present fabrication and characterization procedures of devices for circuit
quantum electrodynamics (cQED). We have made 3 GHz cavities with quality
factors in the range 10^4--10^6, which allow access to the strong coupling
regime of cQED. The cavities are transmission line resonators made by
photolithography. They are coupled to the input and output ports via gap
capacitors. An Al-based Cooper pair box is made by ebeam lithography and Dolan
bridge double-angle evaporation in superconducting resonators with high quality
factor. An important issue is to characterize the quality factor of the
resonators. We present an RF-characterization of superconducting resonators as
a function of temperature and magnetic field. We have realized different
versions of the system with different box-cavity couplings by using different
dielectrics and by changing the box geometry. Moreover, the cQED approach can
be used as a diagnostic tool of qubit internal losses.
