Scanning Near-Field Millimeter-Wave Microscope: Application to a Vector-Coding Technique

The purpose of this paper is to propose an evanescent field-scanning millimeter-wave microscope to bridge the frequency gap that currently exists in probe microscopy. The method is supported by the use of a six-port-based reflectometer operating at 35 GHz in association with a microfabricated resonant micro stripline probe. The simplicity of the method makes it suitable for an industrial context and offers integration possibilities to gain in compacity, reliability, and time operation, in particular. This millimeter-wave microscope is well suited for the characterization of conductors and local electromagnetic properties of dielectrics. The resolution of the probe is experimentally verified by scanning gold lines deposited on a silicon substrate. In addition to the demonstration of the system, we propose to discuss various probe parameters that can be considered to design evanescent millimeter-wave probes (EMPs) for different applications. An original use of the system is suggested through a vector-coding technique of digital information that makes use of the real and imaginary parts of the reflection coefficient.