Phase Perturbation as a Measurement Metric: A Novel Noncontact In-Line Production Measurement Through an All-Electronic Millimeter-Wave System Tracking Millidegree Perturbations in Phase

The market value for the plastics manufacturing industry is projected to exceed US$700 billion in the coming decade [1]. Technology for reliable quality control is an essential component of the manufacturing process. Present technology for monitoring the thickness profile of manufactured plastics typically makes use of interferometry with a white-light (broadband or tunable-wavelength) laser source. [2]-[5]. While this method has found satisfactory implementation as a quality control mechanism to monitor deviations in the thickness of plastics, the cost and complexity of implementation can be prohibitive. In addition, laser-based time-of-flight terahertz time-domain spectroscopic (THz-TDS) tomography systems have been presented as a suitable alternative; however, a femtosecond pulsed laser is still required to render measurements on the order of a micron (μm) [6].