A dielectric probe for near-field millimeter-wave imaging

A dielectric probe for performing near-field imaging in the millimeter-wave band is presented. The probe consists of a rectangular slab of low-loss dielectric material which is metalized on two sides and sharpened to a point of approximately 20 μm. This structure forms a parallel-plate waveguide which offers broadband operation and strong field enhancement and localization at the tip with a spatial resolutions of λ/250. A method of exciting the probe using a metal rectangular cavity resonator is also described.