MM-wave near-field scanning resistivity microscope

A near-field mm-wave scanning microscope was used to image the resistivity of different materials. This technique uses a resonant slit antenna as a scanning probe which is scanned over the surface under study while the reflection/transmission from the surface is measured. The spatial resolution of the near-field imaging is not limited by the wavelength and may be less than a micron, however, calculation of the field distribution in the near-field imaging is difficult which makes it less quantitative than the far-field imaging. Therefore, the spatial resolution and the contrast in the near-field imaging strongly depend on the probe-sample separation.