Non-contact inspection of Moisture Change Based on CW Terahertz Reflectometry

Abstract

We present a method for measuring water content in a sample using CW terahertz reflectometry. A Vector Network Analyzer (VNA) is used to irradiate a 300 GHz band terahertz wave to a wet sample, and the complex reflection coefficient is measured. The temporal change of the water content is thus observed by analyzing the change of the complex reflection coefficient. By fitting the measurement result with a multi-reflection model, we experimentally confirmed the observation of the moisture change on a paper sample.