Showing papers on "Relative permittivity published in 1981"
TL;DR: In this article, an exact field theory solution for the cylindrical TM/sub 010/ cavity with a coaxial lossy dielectric cylinder is given, and the error in the calculated field solutions is estimated to be less than 1 percent of the true values.
Abstract: An exact field theory solution for the cylindrical TM/sub 010/ cavity with a coaxial lossy dielectric cylinder is given. The error in the calculated field solutions is estimated to be less than 1 percent of the true values. Correction for the cavity holes used to introduce the sample is taken into account. The exact solution shows that the real part of the permittivity (epsilon') is a complex function of both the frequency shift and the change in the loaded Q-factor (Q/sub L/). On the other hand the imaginary part (epsilon") is nearly proportional to delta(1/Q/sub L/) and it has different slopes for varying frequencies. By means of active cavity techniques already reported, experimental measurements on epslion' and epsilon" taken at 2.2 GHz on a number of materials (water, teflon, n-proponal, methanol, etc.) agree with published data within 1 percent even when rising large samples.
117 citations
TL;DR: In this article, the dielectric permittivity, optical transmission spectrum and temperature dependence of resistance were investigated in single crystals of Bi4Ti3O12 and BaBi4Ti4O15.
Abstract: The dielectric permittivity, optical transmission spectrum and temperature dependence of resistance were investigated in single crystals of Bi4Ti3O12 and BaBi4Ti4O15. It is found that the dielectric anomalies previously reported below the Curie temperature are due electron space charges of inhomogeneous distribution in the material and near the non-ohmic electrodes.
58 citations
TL;DR: In this paper, Bordewijk's formula and dipole-dipole correlation were used to measure the dielectric permittivities on compounds having different smectic phases in broad temperature intervals.
Abstract: Dielectric permittivities were measured on compounds having different smectic phases in broad temperature intervals. Both the parallel and the perpendicular component of permittivity are given and the variationsare interpreted. The intensity of the low frequency dielectric dispersion is interpreted by Bordewijk's formula and dipole-dipole correlation. The temperature dependences of the relaxation time in the different liquid crystalline phases are given. A small break was found at the N-SmA, SmA-SmC, SmB-SmF phase transitions, an order of magnitude change at the SmA-SmBand SmC-SmB phase transition, and a definite stepat the SmF-SmG phase transition. The big change at these last three phase transitions is interpreted by the appearance of the collective librational modes.
46 citations
TL;DR: In this paper, the relationship between Maxwell's equations and radiative-transport theory is studied for isotropic, nondispersive media that have arbitrary permittivity variations, and it is demonstrated that the postulates of transport theory are consistent with Maxwell's equation if the characteristics of the medium and the fields are such that the field-correlation tensor possesses certain properties and if the relative permittivities fluctuations in the medium are small in comparison with unity and have correlation lengths that satisfy appropriate requirements.
Abstract: The relationship between Maxwell’s equations and radiative-transport theory is studied for isotropic, nondispersive media that have arbitrary permittivity variations. It is demonstrated that the postulates of transport theory are consistent with Maxwell’s equations if the characteristics of the medium and the fields are such that the field-correlation tensor possesses certain properties and if the relative permittivity fluctuations in the medium are small in comparison with unity and have correlation lengths that satisfy appropriate requirements.
43 citations
TL;DR: In this article, the complex relative permittivity of 1-heptanol, 3-hexanol and 3-methyl-2hexanol has been measured from -30 degrees C to 20 degrees C at pressures up to 350 MPa in the range between 50 Hz and 6 MHz.
Abstract: The complex relative permittivity of 1-heptanol, 3-heptanol, 3-methyl-2-hexanol and 2-methyl-2-hexanol has been measured from -30 degrees C to 20 degrees C at pressures up to 350 MPa in the range of frequencies between 50 Hz and 6 MHz. The dispersion in 1-heptanol and 3-heptanol is well characterised by the Debye equation, whereas the other two materials exhibit more than one relaxation time. The activation parameters are calculated and are found to be strongly dependent on the position of the hydroxyl group, and in the case of the branched isomers, of the methyl group. These results are compared with those in the literature for similar octanol isomers, and are discussed in terms of their dependence on liquid structure. The existence of closely ordered and loosely ordered chains is proposed to explain the results.
37 citations
TL;DR: In this paper, RF-sputtered tantalum pentoxide films on silicon substrates were thermally oxidized at 500°C, and Ellipso-metric measurements showed that these films were uniform in refractive index except for a narrow region of tapered index at the silicon interface.
Abstract: Tantalum pentoxide is of interest as an alternative dielectric to SiO 2 for MOS devices. In the present work, RF-sputtered tantalum films on silicon substrates were thermally oxidized at 500°C. Ellipso-metric measurements showed that films made in this way were uniform in refractive index except for a narrow region of tapered index at the silicon interface. Capacitance measurements gave a relative permittivity of about 26, in the range shown by anodic Ta 2 O 5 films. The conduction currents depended on the oxidation period but were comparable to or slightly better than reported for CVD Ta 2 O 5 .
31 citations
TL;DR: In this paper, two simple methods are presented for the measurement of the dielectric permittivity of low-loss microstrip substrates, which are not wasteful of substrate material.
Abstract: Two simple methods are presented for the measurement of the dielectric permittivity of low-loss microstrip substrates. The permittivity associated with a specific length of microstrip may be obtained. The methods are not wasteful of substrate material.
25 citations
TL;DR: In this paper, the propagation of subsurface radar pulses in complex dielectric media is studied numerically, and the model waveform is a 10-ns sinusoidal cycle, and media properties are similar to those of moist ground or sea ice.
Abstract: The propagation of subsurface radar pulses in complex dielectric media is studied numerically. The model waveform is a 10-ns sinusoidal cycle, and the media properties are similar to those of moist ground or sea ice. When the real part of the dielectric permittivity is frequency independent and the imaginary part is dominated by the dc resistivity, amplitudes of the positive and negative half cycles unbalance, and the sinusoidal zero crossing is delayed from its normal position. In these cases, if reflector depth is known, the dielectric constant can be measured from the time delay of the leading edge of the signal, and the dc resistivity can be estimated from a comparison of the input and output pulse power spectra. When dielectric permittivity is frequency dependent through a simple relaxation process, waveform distortion depends on relaxation frequency. In addition, if reflector depth is known, the dielectric relaxation parameters es and e∞ may be estimated when the medium relaxation frequency lies above and below the major portion of the pulse bandwidth, respectively.
24 citations
TL;DR: In this article, a non-local dielectric response to an electric field at different points is correlated over regions comparable with the local microstructure, and the resulting effects are predicted to be larger than those expected for field penetration into the metal electrodes.
22 citations
Patent•
3M1
TL;DR: In this paper, a permanently elastic dielectric composition comprising a resilient base material, an electrically polarizable component having low electrical conductivity, and a component displaying metal conductivity was proposed.
Abstract: A permanently elastic dielectric composition comprising a resilient dielectric base material, an electrically polarizable component having low electrical conductivity to increase the relative dielectric constant of the composition, and a component displaying metal conductivity for maintenance of the relative dielectric constant at high power frequencies.
21 citations
TL;DR: In this article, an equation for the field dependence of relative permittivity of liquids was deduced for both normal and anomalous dielectric saturation as well as on the structure-breaking or structure-making effect of the field.
Abstract: An equation is deduced for the field dependence of relative permittivity of liquids making allowance for the field dependence of the Kirkwood g factor too. The equation gives predictions on both normal and anomalous dielectric saturation as well as on the structure‐breaking or structure‐making effect of the field. Comparison with experimental data indicates that the field dependence of the g factor can alter significantly the nonlinear coefficient Δe/E2 calculated for some alcohols, water, and nitrobenzene. Comparison is also made with approximations, published previously. It is indirectly confirmed that the dielectric behavior of liquids can be described by the same equation even in the vicinity of ions in electrolyte solutions, provided that the average field strength, calculated on the basis of the lattice model of electrolytes, does not exceed the value of about 104 esu. This is about 100 times stronger than the maximum field applied in macroscopic measurements of the nonlinear coefficient.
TL;DR: In this paper, the relative permittivity and electrical conductivity of dispersed resin beads from the dielectric relaxation data were analyzed on the basis of two theoretical equations: one proposed by Wagner for dilute disperse systems, and the other derived by Hanai for concentrated disperse systems.
Abstract: Dielectric measurements on suspensions of an ion-exchange resin, Sephadex G-25, in water, were carried out over the frequency range 30 Hz to 1.7 MHz. The marked dielectric relaxations observed were assigned to interfacial polarization. To evaluate the relative permittivity and electrical conductivity of the dispersed resin beads from the dielectric relaxation data, the observed data were analysed on the basis of two theoretical equations: one proposed by Wagner for dilute disperse systems, and the other derived by Hanai for concentrated disperse systems. The results of this data analysis showed that more suitable values for the relative permittivity and electrical conductivity of the beads in suspension were obtained from Hanai's equations.
TL;DR: In this paper, a simple method is presented for analysis of wire antennas assembled from arbitrarily interconnected straight-wire segments, which are completely or partially covered with a dielectric coating.
Abstract: A simple method is presented for analysis of wire antennas assembled from arbitrarily interconnected straight-wire segments, which are completely or partially covered with a dielectric coating. The thickness of the coating is assumed to be not larger than about the radius of the wire, and its relative permittivity not larger than 10. The method is based on the so-called two-potential integro-differential equation combined with polynomial approximation of current. Numerical results are found to be in very good agreement with experiments.
TL;DR: In this paper, the effect of shielding on the dispersion, characteristic impedance, and the effective dielectric constant of the slot line on a double layer dielectrically constrained MIC was analyzed.
Abstract: This paper presents a rigorous analysis of a) slot line on a double layer dielectric substrate, and b) slot line sandwiched between two dielectric substrates. The structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The dielectric substrates are assumed to be isotropic and homogeneous and are of arbitrary thickness and relative permittivity. The conducting enclosure and the zero thickness metallization on the substrate, are assumed to have infinite conductivity. The effect of shielding on the dispersion, characteristic impedance, and the effective dielectric constant are illustrated. These results should find application in the design and fabrication of MIC components and subsystems.
TL;DR: In this paper, the dielectrophoretic response of different solids is investigated in liquid media of various permittivities and resistivities, which is found to be frequency dependent.
Abstract: The dielectrophoretic response of different solids is investigated in liquid media of various permittivities and resistivities. The solids investigated had a wide range of both relative permittivity (3.8 to 350) and resistivity (10-4 to 1016 Omega m). The use of dioxane and water solutions provided liquid media of controllable relative permittivity in the range 2.2 to 80. The response, which is found to be frequency dependent, is determined for various combinations of insulating and conducting materials at three frequencies: 102 Hz, 104 Hz and 2.55 MHz. The results show that the resistivities of the materials exercise a control over the response comparable to that of their relative permittivities. The correlation of the observed response with that predicted using a theory developed for non-insulating materials is discussed.
TL;DR: In this paper, simple analytical relations for evaluating the components of complex relative permittivity of semiconductors using a cavity perturbation technique for spherical samples are presented, which yield remits of almost the same accuracy obtained by computer solutions of a transcendental equation for samples with resistivity up to about 1Omega-cm.
Abstract: Simple analytical relations for evaluating the components of complex relative permittivity of semiconductors using a cavity perturbation technique for spherical samples are presented. The relations although derived under a simplifying approximation yield remits of almost the same accuracy obtained by computer solutions of a transcendental equation for samples with resistivity up to about 1Omega-cm.
DOI•
01 Aug 1981TL;DR: In this article, the analysis of a step discontinuity in relative permittivity of a single-mode dielectric slab waveguide excited in the dominant TE mode is presented based on the Wiener-Hopf technique.
Abstract: The analysis, based on the Wiener-Hopf technique, of a step discontinuity in relative permittivity is presented for a single-mode dielectric slab waveguide excited in the dominant TE mode. The Wiener-Hopf equation is obtained by applying the Fourier transform together with the proper boundary and edge conditions. Because of the complicated functions involved, the factorisation and decomposition are obtained numerically by applying Lee-Mittra and Noble techniques. The solutions for the reflected and transmitted fields contain infinite number of constants which satisfy the infinite dimensional algebraic simultaneous linear equations. However, convergent solutions of field components can be obtained by using only a few terms. The accuracy of the results is confirmed by good agreement with previously reported data.
TL;DR: In this article, the permittivity of glycerol at 2.00 GHz and 23±0.2°C was investigated at 4.00, 3.00 and 4.3 GHz.
Abstract: Measurements are reported of the permittivity of glycerol at 2.00,3.00, and 4.00 GHz and 23±0.2 °C. (AIP)
TL;DR: In this paper, the ambiguity is removed by introducing a new experimental parameter and the calculations are very simple, in the case of disc samples, in which the theory of disc sampling is detailed.
Abstract: The ambiguity is removed by introducing a new experimental parameter and the calculations are very simple. The theory, in the case of disc samples, is detailed. Measurements for some standard materials are presented.
TL;DR: An algorithm for the lumped-capacitance method is described in this paper, which enables computation of permittivity and losses of ferroelectric crystals to be made, and a graphical method for the solution of the algorithm by means of specially prepared diagrams is proposed.
Abstract: An algorithm for the lumped-capacitance method is described which enables computation of permittivity and losses of ferroelectric crystals to be made. The graphical method for the solution of the algorithm by means of specially prepared diagrams is proposed. The method gives the possibility of finding from the measurement data a proper solution independently of the geometrical dimension of the sample.
TL;DR: In this paper, a method of microwave dielectric spectroscopy, which allows to investigate the permittivity of needle-shaped anisotropic crystals with the diameter ranging from a few microns to some millimeters, is described.
Abstract: The method of microwave dielectric spectroscopy which allows to investigate the dielectric permittivity of needle-shaped anisotropic crystals with the diameter ranging from a few microns to some millimeters for practically all possible value of dielectric permittivity under progressive wave conditions is described. Resonance dielectric dispersion in addition to the one caused by soft phonon mode in the vicinity of the phase transition in SbSI and SbS0.7Se0.3 I chain crystals at microwaves has been discovered.
TL;DR: In this article, a microwave bridge method is discussed for measuring the complex permittivity of dielectric materials, including benzene, carbon tetrachloride, petrol, and kerosene.
Abstract: A microwave bridge method is discussed for measuring the complex permittivity of dielectric materials. The underlying principle of the technique along with the experimental results is presented. The complex permittivities of benzene, carbon tetrachloride, petrol, and kerosene are illustrated at a few frequencies in X-band. The variation of the dielectric properties of petrol-kerosene mixture is also studied.
TL;DR: In this paper, the dielectric permittivity and pyroelectric coefficient of mixed crystals of TGS and TGFB are reported, and it has been shown that L-alanine doped mixed crystals can be good elements for IR detectors.
Abstract: Dielectric permittivity and pyroelectric coefficient of mixed crystals of TGS and TGFB are reported. It has been shown that L-alanine doped mixed crystals can be good elements for IR detectors.
TL;DR: In this paper, it was shown that to a high degree of accuracy the complex relativity permittivity for a gas dielectric in very dilute solution in a nonpolarsolvent is given theoretically for symmetric polar molecules by the modification of a relation, which essentially goes back to Rocard.
Abstract: It is shown that to a high degree of accuracy the complex relativity permittivity for a gas dielectric or for a liquid dielectric in very dilute solution in a nonpolarsolvent is given theoretically for symmetric polar molecules by the modification of a relation, which essentially goes back to Rocard. When the molecules are linear or spherical, the modified relation is particularly simple. There is no simple relation for complex permittivity when the polar molecules are asymmetric. Thus in comparing the theory of rotational Brownian motion with the results of dielectric relaxation experiments it would seem advisable at the present stage to focus attention on experiments performed with symmetric polar molecules, preferably spherical or linear.
TL;DR: In this article, the complex permittivity of many soil samples were measured using the evanescent waveguide technique at 9 GHz and interpreted using Wiener's theory for dielectric mixtures to evaluate the degree of binding of water in soils.
Abstract: Measurements of the complex permittivity of many soil samples were conducted using the evanescent waveguide technique at 9 GHz. The complex permittivity was taken as a function of moisture content. The experimental results were interpreted using Wiener's theory for dielectric mixtures to evaluate the degree of binding of water in soils.
TL;DR: In this article, it was shown that bend radii down to four guide wavelengths are acceptable for waveguides with a relative permittivity of 10 and that bend radius below 4 guide wavelengths is not prohibitive.
Abstract: A crucial parameter in the design of compact dielectric waveguide integrated circuits is the minimum bend radius below which radiation losses become prohibitive. It is shown that, for waveguides with a relative permittivity of 10, values of bend radii down to four guide wavelengths are acceptable.
15 Jun 1981
TL;DR: In this article, the authors proposed a method to solve the problem of unstructured data, which is not available at time of publication, by using a set of hand-crafted features.
Abstract: Text of paper not available at time of publication.