Near-field scanning microwave probe based on a dielectric resonator

We report a near-field microwave microscopy based on a novel scanning probe -a long and narrow slot microfabricated on the convex surface of the dielec tric resonator. The probe is mounted in the cylindrical waveguide. Tunable coupling to the probe is effectuated through the variable air gap. The whol e probe is very compact, has a coaxial input, operates at 25-30 GHz, has a spatial resolution of 1-10 mum and, most important, has a low impedance of similar to 20 Omega. This allows us to use it for characterization of metal lic layers with high conductivity, in particular, thickness mapping. (C) 20 01 American Institute of Physics.