Presenter

Mrs. Bin Zhu [Email]

Abstract

Last decade, scanning near field Millimeter and Terahertz wave microscopy have attracted much attention due to its unique sub-wavelength focusing properties. Millimeter and Terahertz waves can penetrate a large variety of visibly opaque materials such as plastics, ceramics, cloths,… enabling novel Non Destructive Testing (NDT), sensing and imaging applications. Three types of near-field setups, comprising aperture and aperture-less solutions, are designed featuring different combinations of penetration depth and resolution. Firstly, a circularly tapered dielectric probe is designed as a near-field probe coupled to free space, and enabling both transmission and reflection operation. Secondly, the near-field operation of different rectangular tapered dielectric probes coated with evaporated aluminum layers on the sides and coupled with a standard metal waveguide is compared. Neither of them allows transmission operation but benefit from high resolution determined by the dimension of the end facet of the probe. Thirdly, a combination of aperture and aperture-less probe is disclosed. A circularly tapered Teflon probe acts as a near-field illumination probe of a metal needle with minimal stray effects. This combined solution offers much higher resolution, determined by the dimension of the needle point, but offers only very limited penetration. Both theoretical and experimental analysis for these three types of near-field probes are executed in this work. Finally, a set of possible attractive applications, including water content sensing, are discussed.

Short CV

Master in Engineering: Communication and Information Systems