Non-Destructive Dielectric Constant Measurement of Low-Loss Dielectric Slabs Using Wideband Autocorrelation Radiometry

摘要

In this paper, a novel technique for measuring the dielectric constant of a low-loss layer without the need for sample preparation is presented. This technique inspired by a passive microwave remote sensing method, known as wideband autocorrelation radiometry (WiBAR), which remotely measures the microwave propagation time difference of multipath microwave emission from low-loss layered surfaces such as dry snowpack and freshwater icepack. This time delay is dependent on the incident angle. Using the measured time delay at two different incident angles, the real part of the dielectric constant and the thickness of the loss-less slab can be directly measured. An X-band instrument fabricated from commercial-off-the-shelf (COTS) components are used to characterize the freshwater lake ice at the University of Michigan Biological Station. The measurements were performed in H-pol configuration for a lake icepack of about 36 cm from nadir to 59°.