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Showing papers on "Relative permittivity published in 1973"


Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the interfacial effects arising in electrical measurements of rocks, when a two-electrode system is used, via the Maxwell-Wagner effect, and concluded that it is necessary to have volume charge accumulations at interfaces within the sample and at the electrode-sample interface in order to have electrical steadystate conditions in rock samples.
Abstract: The interfacial effects arising in electrical measurements of rocks, when a two‐electrode system is used, are analyzed via the Maxwell‐Wagner effect. The similarity in electrical behavior between rock samples and heterogeneous dielectrics with nonnegligible ohmic conductivities leads to a general analysis of the Maxwell‐Wagner effect. We conclude that, in general, it is necessary to have volume charge accumulations at interfaces within the sample and at the electrode‐sample interface in order to have electrical steady‐state conditions in rock samples. The expression for the charge accumulation at the interface as a function of frequency is obtained as well as expressions for the effective dielectric permittivity in a composite material; the relaxation time associated with the charge accumulation and that of the effective dielectric permittivity are the same. Given a sample consisting of two different materials, it is shown that whenever both components have nonnegligible ohmic conductivities, the imaginar...

58 citations


Journal ArticleDOI
M. Matsuhara1
TL;DR: In this article, a method of analysis of dielectric waveguides using a variational method is presented, which can be applied to dielectrics with any general permittivity distribution.
Abstract: In this paper, a method of analysis of dielectric waveguides using a variational method is presented. This method can be applied to dielectric waveguides with any general permittivity distribution. As examples, numerical calculations for dielectric waveguides with rectangular cross-sectional shape and quadratic inhomogeneous permittivity distribution are given.

47 citations


Journal ArticleDOI
TL;DR: In this article, reflected power profiles were used to determine complex dielectric permittivity of low, medium, and high permittivities of low and high dielectrics by one single method if nonideal plunger properties are taken into account.
Abstract: Computer analysis of reflected power profiles allows accurate determination of complex dielectric permittivity of low, medium, and high permittivity liquids by one single method if nonideal plunger properties are taken into account. For low loss measurements account is taken of the losses in the waveguide walls. For medium and high permittivity liquids, dumbell plunger design leads to important errors due to higher mode excitation and propagation.

40 citations


Journal ArticleDOI
G. J. Sprokel1
TL;DR: In this article, the permittivity of doped nematics was found to increase approximately as (1/ω)2 at low frequency and the effect was accounted for by considering the space charge resulting from dissociation of the dopa.
Abstract: The permittivity of doped nematics is found to increase approximately as (1/ω)2 at low frequency The effect is accounted for by considering the space charge resulting from dissociation of the dopa

39 citations


Journal ArticleDOI
TL;DR: In this paper, the anodization of Si in a 1 MHz oxygen plasma is described, and the dependence of ionic current on oxide field strength is found to be dependent on oxide thickness.
Abstract: The anodization of Si in a 1 MHz oxygen plasma is described. In‐situ film thickness measurements were made using a single angle "s" light reflectance technique and this data, coupled with information on the variation of sample voltage with thickness, was used to determine the dependence of ionic current on oxide field strength. The data for a given oxide thickness could be described by an equation of the form given by the theory of ionic conduction by a thermally activated, field‐assisted process. However, the ionic current and, in paticular, the oxide field strength were dependent on oxide thickness. MOS C‐V measurements on oxides of different thickness indicated a change in flatband voltage that could be attributed to a progressive build‐up of positive charge within the oxide. This space charge could be reduced by a low temperature annealing treatment. The oxides were found to be slightly absorbing optically, to have a relative permittivity in the range 3.5–3.9, and to possess good insulation properties as long as the oxide thickness did not exceed about 2500â.

36 citations


Journal ArticleDOI
TL;DR: In this article, a cavity test fixture was constructed and tested to experimentally demonstrate the capabilities of integrated finline, and the results were analyzed to determine the manner in which the guide wavelength and unloaded Q factor varied.
Abstract: To experimentally demonstrate the capabilities of integrated finline, a cavity test fixture was constructed and tested. The results were analysed to determine the manner in which the guide wavelength and unloaded Q factor varied. The measured unloaded Q factor of integrated finline was found to be two to three times better than that of microstrip. Owing to the low loss of integrated finline, its freedom from tight tolerances and compatibility with hybrid devices, this new transmission line is well suited to millimetre integrated circuits.

31 citations



Journal ArticleDOI
TL;DR: In this article, the relative permittivity and loss factor of thiourea, in a frequency range from 1.6 Hz to 20 MHz, have been examined carefully throughout the temperature region in which phase transitions occur.
Abstract: The relative permittivity and loss factor of thiourea, in a frequency range from 1.6 Hz to 20 MHz, have been examined carefully throughout the temperature region in which phase transitions occur. The narrow ferroelectric region, phase III, has been studied more thoroughly than previously and the existence of additional distinct ferroelectric regions within phase II has been established. In each of the ferroelectric regions, there is dispersion in the permittivity and dependence of the permittivity on DC bias field.

18 citations


Journal ArticleDOI
TL;DR: In this paper, expressions for the reflection and transmission power coefficients were derived for the case where a plane wave is obliquely incident on a dielectric slab in which the relative permittivity decreases symmetrically according to a 1/z^{2} law from a given maximum value at the plane of symmetry and tends towards unity at the two faces of the slab.
Abstract: Expressions for the reflection and the transmission power coefficients are derived for the case where a plane wave is obliquely incident on a dielectric slab in which the relative permittivity decreases symmetrically according to a 1/z^{2} law from a given maximum value at the plane of symmetry and tends towards unity at the two faces of the slab. The effect of the curvature and other parameters governing the inverse square profile on the transparency property of the material at radar frequencies has been studied within a large d/\lambda range where d is the half-slab thickness and \lambda the wavelength of the incident wave.

16 citations


Journal ArticleDOI
TL;DR: In this paper, more realistic trends for the electrical characteristics of rocks with high loss and high permittivity were demonstrated by using the air gap and several correction techniques at the electrode-specimen contacts.
Abstract: In this paper, perhaps for the first time, more realistic trends for the electrical characteristics of rocks with high loss and high permittivity are demonstrated. With decrease in frequency, below 105 hz, the dissipation factor of these rocks generally increases, while the real relative permittivity generally levels off at about l0 to 30. These results were obtained by use of the airgap and several correction techniques at the electrode‐specimen contacts. The rocks used in these measurements contain a certain amount of moisture since they were dried in room atmosphere. When these rock samples are measured by the conventional electrode contact method, the real relative permittivity rises with decrease in frequency, while the dissipation factor levels off at a value of about 1.0 or below. These results are contrary to those obtained by measurements with the airgap technique and by applying several correction factors. For a serpentinite specimen, real relative permittivity measured by the conventional conta...

15 citations


Journal ArticleDOI
TL;DR: In this article, a general computer program is described for precisely calculating dielectric properties of high-or low-loss materials from short-circuited coaxial, cylindrical, or rectangular waveguide measurements on samples in contact with the short- circuit termination.
Abstract: A general computer program is described for precisely calculating dielectric properties of high-or low-loss materials from short-circuited coaxial, cylindrical, or rectangular waveguide measurements on samples in contact with the short- circuit termination. Slotted-section measurements are corrected for the influence of the slot on the propagation constant of the waveguide. Corrections are included for wall losses in the waveguide, and differences between measurements in vacuum and in air are also taken into account. Three sets of possible values for the relative dielectric constant and loss factor, loss tangent, and conductivity are printed out corresponding to three solutions of the complex transcendental equation. Data for up to fifty samples are stored, and a summary table includes the set of dielectric properties coresponding most closely to the estimated dielectric constant for each sample.

Journal ArticleDOI
TL;DR: In this paper, a method for measuring the complex relative permittivity of liquids is described, where the liquid under test is contained in a narrow glass tube (volume < 0.5 ml) which is placed concentrically along the axis of the cavity resonator.
Abstract: A method is described for measuring the complex relative permittivity of liquids. Circular cylindrical TE011-, TM010- and coaxial-line-resonators are used. The liquid under test is contained in a narrow glass tube (volume<0.5 ml) which is placed concentrically along the axis of the cavity resonator. Besides the knowledge of the diameter of the glass tube and the dimensions of the resonator only frequency measurements are required. The accuracy of the method (error±5% of the absolute value for both, the real- and imaginary part of the permittivity) is comparable to other methods requiring a larger amount of liquid. Furthermore, permittivity variations can be measured very sensitively because these are indicated by shifts of the resonance frequency as well as changes of the quality constant, which can both be determined with an error smaller than 0.5%. Some experimental results for water and an aqueous phospholipid suspension are given to demonstrate the accuracy of the method.

Journal ArticleDOI
A.C. Lynch1
01 Aug 1973
TL;DR: In this article, it was shown that the correction for edge capacitance is usually negligible when permittivity is measured by the adjustment of electrode separation so as to restore the capacitance, after removal of the specimen, to its previous value.
Abstract: The correction for edge capacitance, which is usually calculated by Kirchhoff's formula, can be separated by graphical methods into components at various distances from the edge, and so into components which fall within the area of a disc specimen and those which are entirely outside it. In this way, it can be shown that the correction for edge capacitance is usually negligible when permittivity is measured by the adjustment of electrode separation so as to restore the capacitance, after removal of the specimen, to its previous value. The correction to be applied to the observed value of loss tangent is typically about ?3% of the loss tangent. The paper is a companion to that by Blanco White (p. 939).

Journal ArticleDOI
TL;DR: In this article, the problem of diffraction of an E-polarized plane wave by a perfectly conducting wedge, having the illuminated side loaded with a thin dielectric slab of which the relative permittivity is not much larger than unity, is treated.
Abstract: The problem of diffraction of an E-polarized plane wave by a perfectly conducting wedge, having the illuminated side loaded with a thin dielectric slab of which the relative permittivity is not much larger than unity, is treated. The solution is given in an integral form, consisting of geometrical optics and associated diffraction terms, by applying an approximate boundary condition at the dielectric surface. The diffraction integrals involved are evaluated asymptotically in terms of Fresnel's integrals. Using the reciprocity principle, the results are extended to the cylindrical-wave excitation. The validity of the results is verified by comparison with experiment for the case of a dipole-fed dielectric-loaded strip.

Journal ArticleDOI
TL;DR: In this paper, the authors describe recent measurements of the complex permittivity of ice at 96.5 GHz and the relative premittivity is more nearly 3 than the previously reported value of 2.
Abstract: This communication describes recent measurements of the complex permittivity of ice at 96.5 GHz. The relative premittivity e′ is more nearly 3 than the previously reported value of 2. Better temperature control of the ice samples resulted in a more accurate measure of the dielectric loss of ice at this frequency.

Journal ArticleDOI
TL;DR: In this article, both complex and real multipole resonance frequencies in radar cross section (RCS) of a dielectric sphere are studied in some detail, and the results show the possibility of highly accurate measurement at microwave frequencies.
Abstract: Both complex and real multipole resonance frequencies in radar cross section (RCS) of a dielectric sphere are studied in some detail. Charts of real resonance frequencies and peak values are presented, which are then used to determine the complex permittivity of the material from the resonance measurement. The results show the possibility of highly accurate measurement at microwave frequencies. This method is unique in several respects and has many advantages.

Journal ArticleDOI
TL;DR: In this article, a new method is suggested to determine the dielectric permittivity of materials, by means of time domain reflectometry (TDR), for frequencies v ≳ 4 × 10 7 Hz independent of the value of the relaxation frequency involved.


Journal ArticleDOI
TL;DR: In this paper, a stripline method is described for the rapid measurement of dielectric permittivity, which can be instrumented to be direct-reading in terms of?r?.
Abstract: A stripline method is described for the rapid measurement of dielectric permittivity ?r? which can be instrumented to be direct-reading in terms of ?r?. The measurement is independent of loss factor and is applicatble for permittivities from 2 up to 20 with a reasonable accuracy. Above about 20, the accuracy falls with increasing ?r?.

Journal ArticleDOI
TL;DR: In this paper, an effective permittivity is defined which characterizes the electrical coupling properties of acoustoelectric surface waves, and relationships between this quantity and other parameters, such as Δv/v, used in evaluating active and passive surface wave devices.
Abstract: An effective permittivity is defined which characterizes the electrical coupling properties of acoustoelectric surface waves. Relationships are established between this quantity and other parameters, such as Δv/v, used in evaluating active and passive surface‐wave devices. A simple method for computing the effective permittivity is described which is shown to be more accurate than other methods used to date.

Journal ArticleDOI
TL;DR: In this paper, a flow method is reported for the measurement of the permittivity and dielectric loss factors of liquids in the microwave region, and it is estimated that with the method it is possible to measure permittivities to at least +or-0.5% or +or 0.5*10-3 or + or 2% whichever is the greater.
Abstract: A flow method is reported for the measurement of the permittivity and dielectric loss factors of liquids in the microwave region. It is estimated that with the method it is possible to measure permittivities to at least +or-0.5% and dielectric loss factors to +or-0.5*10-3 or +or-2% whichever is the greater.


Journal ArticleDOI
TL;DR: In this paper, the asymptotic solution for the diffraction of an E -polarized plane incident electromagnetic wave by a conducting wedge, whose illuminated surface is loaded with a dielectric slab of small thickness and relative permittivity, is employed to derive a ray optical diffraction coefficient for the edge.
Abstract: The asymptotic solution for the diffraction of an E -polarized plane incident electromagnetic wave by a conducting wedge, whose illuminated surface is loaded with a dielectric slab of small thickness and relative permittivity, is employed to derive a ray optical diffraction coefficient for the edge.

Patent
27 Nov 1973
TL;DR: In this paper, a microwave slit line composed of a dielectric carrier substrate having a relatively low Dielectric constant, a metal layer on one surface of the substrate and having a portion removed to form the required slit, and covering the side of the line which faces away from the substrate was proposed.
Abstract: A microwave slit line composed of a dielectric carrier substrate having a relatively low dielectric constant, a metal layer on one surface of the substrate and having a portion removed to form the required slit, and a dielectric plate having a relative dielectric constant >/= 8 and covering the side of the line which faces away from the substrate.

Journal ArticleDOI
01 Apr 1973
TL;DR: In this article, a polythene tape in association with sulphur hexafluoride under pressure is proposed for underground transmission cables, which has low dielectric loss, low relative permittivity and high thermal conductivity.
Abstract: Polythene tape in association with sulphur hexafluoride under pressure is an attractive dielectric for underground transmission cables because it has low dielectric loss, low relative permittivity and high thermal conductivity. Unfortunately, polythene tape has a high coefficient of thermal expansion, and care is consequently needed in the design of the conductor electrostatic screen to achieve adequate electric strength. Because of the low thermal conductivity of sulphur hexafluoride between layers of tape, good contact needs to be obtained by controlling the interfacial pressure in the dielectric wall to achieve good heat transfer. It has been demonstrated by work on models and 650 mm2 275 kV cable that this type of cable is technically feasible

Journal ArticleDOI
TL;DR: In this article, a system capable of dielectric permittivity measurements in liquids and solids in the temperature range 10-300 K and at pressures to 11 kilobar is described.
Abstract: A system that is capable of dielectric permittivity measurements in liquids and solids in the temperature range 10–300 K and at pressures to 11 kilobar is described. A brief discussion of some experimental data and sources of error is included.

ReportDOI
01 Jul 1973
TL;DR: In this article, the real and imaginary components of dielectric constant were determined for basalt, granite and quartzite in the frequency range 10MHz to 4 GHz in the presence of activated particulate diffusion.
Abstract: : The real and imaginary components of dielectric constant were determined for basalt, granite and quartzite in the frequency range 10MHz to 4 GHz. The variation of dielectric permittivity with temperature was determined from room temperature to 450C. No dielectric dispersion or rock relaxation was observed in the frequency range investigated. Hence, the rock relative dielectric constant and relative loss showed mild variation with frequency with no discontinuity or sharp peaks as those previously observed in the low frequency range (up to 2 KHz). The temperature coefficient of the relative dielectric constant was related to the isobarric thermal expansion coefficient of the rock. The relative dielectric loss of basalt and granite followed an Arrhenius exponential increase with temperature suggesting the loss mechanism to be associated with activated particulate diffusion in the rock lattice. Activation energy for the conductance process depended on the temperature range and appeared to be independent of frequency. Quartzite showed an anomalous temperature variation of its conductivity. (Author)



Journal ArticleDOI
TL;DR: In this paper, the frequency dependence of conductivity in mature films of amorphous ZnTe (a-ZnTe) was found to be consistent with the hopping type conduction model proposed by Jonscher with a quadratic sequence of firing times.
Abstract: The frequency dependence of conductivity in mature films of amorphous ZnTe (a-ZnTe) is found to be consistent with the hopping type conduction model proposed by Jonscher with a quadratic sequence of firing times The frequency dependent part of the conductivity obeys a power law relation of the form where "n" takes the value of 050 ± 001 in the temperature range 167 K < T < 300 K, whereas the real part of the relative permittivity follows an ωn−1 dependence Effects due to dipole relaxation are also observed and can mask the hopping conduction observed No well-defined single activation energy is observed for the conductivity over the temperature range studied