Microwave power spectra of variable thickness sub-micron bridges

The frequency variation of the radiated power and linewidth of variable thickness bridges from 2 to 18 GHz is reported. A new, simple technique for fabricating these bridges using electron beam lithography is described. The measured power is found to be in unexpectedly good agreement with that calculated using the resistively shunted junction model. The linewidth data are in striking disagreement with existing theories.