Frank M. Haran

Simultaneous composition and thickness measurement of paper using terahertz time-domain spectroscopy

We present a noncontact method for quantitative composition and thickness monitoring of flat sheet products using terahertz time-domain spectroscopy. We apply the method to obtain simultaneous measurement of thickness and moisture content of paper sheets. The paper is modeled as an effective medium of water mixed with fibers, and model parameters are estimated from fits to the measured transmission amplitude. We demonstrate the method on two different paper samples and obtain uncertainties that are comparable with existing sensor technology. Monte Carlo simulations indicate that these uncertainties can be reduced further by at least an order of magnitude.

High efficiency coupling devices for guided wave radar-based level sensors

In this work we present novel coupling devices, in terms of feed-throughs and launchers, which are able to increase the efficiency of the electromagnetic power transmission along the propagation chain of guided wave radar (GWR) transmitters for level and interface measurement. The novel concepts are validated by 2D 1COMSOL® axisymmetric simulations which prove that the innovative design improvements are able to increase the electromagnetic efficiency by at least 6 dB. Such novel GWR level transmitters can improve the accuracy and the measurement range of the next generation of GWR level transmitters.

Paper Parameter Estimation Using Terahertz Time-Domain Spectroscopy

We demonstrate a terahertz time-domain technique for measuring thickness, moisture and basis weight of paper. We validate our technique for a sample compressed to different thicknesses and establish uncertainty limits using Monte Carlo simulations.

Paper Parameter Estimation Using Time-domain Terahertz Spectroscopy

We demonstrate a technique for determining the thickness, moisture, and basis weight of paper, using time-domain terahertz spectroscopy. The fundamental uncertainty limits on all three paper processing parameters are competitive with existing sensor technology. Article not available.

Paper parameter estimation using time-domain terahertz spectroscopy

We demonstrate a time-domain terahertz technique for measuring thickness, moisture and basis weight of paper. We validate our technique for a sample compressed to different thicknesses and establish uncertainty limits using Monte Carlo simulations.