Evaluation of complex permittivity of aqueous solution by time domain reflectometry

Dielectric-Relaxation Spectroscopy of Kaolinite, Montmorillonite, Allophane, and Imogolite under Moist Conditions

“…Dielectric measurements in the frequency range of 1 kHz to 20 GHz were performed following the TDR method (Cole et aL, 1980;Mashimo et al, 1987a). In this method, a step-voltage pulse, with a 30-ps rise time and 200-mV height, generated by a tunnel diode passes through a flexible coaxial cable (Suhner Electrics, Ltd., Sucoform 141PE, 50 gl, dc: 26.5 GHz) to the sample surface upon which the applied pulse is reflected.…”

“…Hence, the contribution of dc conductivity to the complex permittivity must be precisely evaluated, especially in the low-frequency range. This evaluation is possible using a reference TDR method (Cole et al, 1980;Mashimo et al, 1987a). If a standard sample with known permittivity is employed as a reference and the conductivity is adjusted to be approximately the same as that of an unknown sample, the complex permittivity of the unknown sample can be obtained as a function of the ratio of the Fourier transforms of the two reflected waves from the known and the unknown samples, respectively.…”

Dynamical behavior of unfreezable molecules restricted in a frozen matrix

“…TDR measuring system equipped a sampling head (HewlettPackard 54121 A) and a mainframe of digitizing oscilloscope (Hewlett-Packard 54121B), covered the frequency range from 10 MHz to 20 GHz. Details of TDR were described in former literatures [5,[11][12][13]. IMA (Hewlett-Packard 4291A) and LCR meter (Hewlett-Packard 4284A) was utilized to cover the range of 1 MHz-1.8 GHz and 20 Hz-1 MHz, respectively.…”

Microwave Dielectric Relaxation of Bound Water to Silica, Alumina, and Silica–Alumina Gel Suspensions

“…A detailed description of this method is presented elsewhere (12). An incident pulse with a rise time of 30 ps generated by a pulse generator passes through a 50 ⍀ coaxial cable and is reflected from the top of the cable, where the sample cell is attached.…”