An experimental technique and associated analysis are described for the measurement of the dielectric constants of liquids at microwave frequencies using an open-ended coax probe. The analysis includes radiative corrections to the probe-liquid interface impedance. The technique is applicable to liquid and liquidlike (e.g., biological) samples, having dielectric constants comparable to water, at...

There is a considerable interest in the dielectric properties of a material under a pressure other than the atmospheric pressure. Most interest seems to stem from chemical reactions or material property modification. We have studied the variation of the dielectric properties of gas under pressure with frequency. A gas, such as LPG, shows an increase in the dielectric constant from 1.002 to 1.05...

Dielectric relaxation of the ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate (EMI+ETS-), is studied using molecular dynamics (MD) simulations. The collective dynamics of polarization arising from cations and anions are examined. Characteristics of the rovibrational and translational components of polarization dynamics are analyzed to understand their respective roles in the microwave an...

An experimental study concerning Ultra Wideband (UWB) Microwave Radar for breast cancer detection is described. A simple phantom, consisting of a cylindrical plastic container with low dielectric constant material imitating fatty tissues and a high dielectric constant object emulating tumour, is scanned with a tapered slot UWB probe antenna between 3.1 to 10.6 GHz. Different calibration schemes...

We report on the high frequency complex permittivity characterization of single-walled carbon nanotubes (SWNT) using broadband and narrowband frequency range techniques. SWNT suspensions, powder and fiber were investigated and the samples were a mixture of semiconducting and metallic nanotubes. Shielded opencircuited coaxial probe (50 MHz to 10 GHz) and dielectric microwave resonators were deve...

A novel NaAgMoO4 material with spinel-like structure was synthesized by using the solid state reaction method and the ceramic sample was well densified at an extreme low sintering temperature about 400°C. Rietveld refinement of the crystal structure was performed using FULLPROF program and the cell parameters are a = b = c = 9.22039 Å with a space group F D -3 M (227). High performance microwav...

We analyzed the complex dielectric and Raman spectra of hydrogen-bond liquids in the microwave to terahertz frequency range. As for water and methanol, the high-frequency component of the dielectric spectrum, i.e., the small deviation from the principal Debye relaxation, clearly corresponds to the Raman spectrum. This indicates that the cooperative relaxation, accompanied by huge polarization f...

We use a near-field scanning microwave microscope to simultaneously image the dielectric constant, loss tangent, and topography in a PbTiO3 crystal. By this method, we study the effects of the local dielectric constant and loss tangent in the geometry of periodic domains on the measured resonant frequency, and quality factor. We also carry out theoretical calculations and the results agree well...

MgTe2O5 ceramics were prepared by solid-state route. These materials were sintered in the temperature range of 640–720 °C. The structure and microstructure of the compound was investigated using x-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. The dielectric properties of the ceramics were studied in the frequency...

Techniques based on the perturbation of cavity resonators are commonly used to measure the permittivity and permeability of samples of dielectric and ferrite materials at microwave frequencies. They are also used to measure the local electric and magnetic field strengths in microwave structures including the shunt impedances of cavity resonators and the coupling impedances of slow-wave structur...