Liu, Xiaoming, and Junsheng Yu. “Characterization of the Dielectric Properties of Water and Methanol in the D-Band Using a Quasi-Optical Spectroscopy.” Scientific Reports 9, no. 1 (December 2019): 18562.
https://doi.org/10.1038/s41598-019-55126-6.
This work presents the measurement of the permittivities of water and methanol in the D-band. Water is a reference medium for dielectric measurement. The dielectric permittivity of water in the millimeter wave range is a fundamental parameter in many applications, and needs to be investigated systematically. The measurement is conducted using a quasi-optical spectroscopy, which is an improved free-space method more suitable for the millimeter wave range. The theoretical formulae are derived using the signal-flow chart method, which is developed specially for multi-layer operation. This model enables one measure liquid samples. A non-calibration method has been developed to retrieve the permittivity. Water and methanol are measured at several temperatures. The measured results agree with published results in a 4% discrepancy. This work will add new measured data to the permittivities of water and methanol over the whole D-band.