Compact near-field microwave microscope based on the multi-port technique

A multi-port based near field microwave-wave microscope is proposed for local characterization of materials with a sub-wavelength resolution of 60 μm at 2.655 GHz (~λ/2000). It is demonstrated that the combination of a four-port reflectometer and a microstrip evanescent microwave probe represents a viable and promising alternative to the costly heterodyne principle. The depth and lateral resolutions of the probe are experimentally verified to evaluate the performances of the system proposed.