Waveguide Probes Using Single Negative Media

In this work, we show that by using single negative (SNG) media, the sensitivity of open-ended near-field waveguide probes can be enhanced. The enhancement is due to the evanescent wave amplification property of SNG media. As a demonstration of the efficacy of the proposed SNG-enhanced probe, we present a numerical study of the case of detecting precursor pitting in aluminum plates. We show that the SNG-enhanced probe achieves 35 times increase in the phase shift due to the presence of the target in comparison to the case of a classical probe. We show that there is an optimum SNG media thickness and an optimum standoff distance that maximize the sensitivity.