Showing papers on "Relative permittivity published in 2003"
TL;DR: In this article, an expression relating the static dielectric permittivity profile for a system nonuniform in one dimension to correlations between the net system dipole moment and the local polarization density was derived.
Abstract: We derive an expression relating the static dielectric permittivity profile for a system nonuniform in one dimension to correlations between the net system dipole moment and the local polarization density. The permittivity profile of a dipalmitoylphosphatidylcholine (DPPC) lipid bilayer in water is calculated from an all-atom 20-ns molecular dynamics simulation. The component of the permittivity parallel to the bilayer shows a nonmonotonic decrease from the value in bulk water to the value in the membrane interior; the interfacial region itself has a very large permittivity, greater than that of bulk water. In high-dielectric regions, obtaining a quantitative estimate of the component normal to the bilayer is not possible because of large numerical uncertainty. However, the calculated correlation function is consistent with a value for the interface at least as large as that of bulk water. In general, the transition to a low-dielectric environment is sharp and is located on the inner border of the region where there is significant probability of finding the polar head groups.
238 citations
TL;DR: Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 10−1-106'Hz and −150-350'°C, respectively as discussed by the authors.
Abstract: Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 10−1–106 Hz and −150–350 °C, respectively We found that the antiferroelectric phase transition temperature of Bi2Ti4O11 decreases with Ba doping In the permittivity studies, we also observed dielectric relaxation peaks shift to higher temperature with increasing frequency Furthermore, in the electric modulus formalism, conducting peaks were uncovered above 150 °C in addition to the dielectric relaxation peak We discussed the mechanisms for the dielectric relaxation and conduction processes based on TiO6 octahedra distortion and a space-charge model
235 citations
TL;DR: In this paper, a melt-spun technique was used to construct composite materials with an anisotropic anisotropy field (HA) of tetragonal Fe3B (∼0.4 MA/m), and the electromagnetic wave absorption properties were measured in the 0.05-20.05 GHz range.
Abstract: Nanocomposites α-Fe/Fe3B/Y2O3 were prepared by a melt-spun technique, and the electromagnetic wave absorption properties were measured in the 0.05–20.05 GHz range. Compared with α-Fe/Y2O3 composites, the resonance frequency (fr) of α-Fe/Fe3B/Y2O3 shifted to a higher frequency range due to the large anisotropy field (HA) of tetragonal Fe3B (∼0.4 MA/m). The relative permittivity (er=er′−jer″) was constantly low over the 0.5–10 GHz region, which indicates that the composite powders have a high resistivity (ρ=∼100 Ω m). The effective electromagnetic wave absorption (reflection loss <−20 dB) was obtained in a frequency range of 2.7–6.5 GHz on resin composites of 80 wt % α-Fe/Fe3B/Y2O3 powders, with thickness of 6–3 mm, respectively. A minimum reflection loss of −33 dB was observed at 4.5 GHz with an absorber thickness of 4 mm.
220 citations
TL;DR: In this article, the relative permittivity and dielectric loss of BZN films were measured with frequencies up to 100 MHz using planar Al2O3/Pt/BZN/PT and Si/SiO2/Pts/BzN/pts/pt capacitor structures with thicknesses in the range of 160 to 170 nm.
Abstract: Near-stoichiometric Bi1.5Zn1.0Nb1.5O7 (BZN) films were deposited by rf magnetron sputtering. The relative permittivity and dielectric loss of BZN films were measured with frequencies up to 100 MHz using planar Al2O3/Pt/BZN/Pt and Si/SiO2/Pt/BZN/Pt capacitor structures. BZN films with thicknesses in the range of 160 to 170 nm exhibited electric field tunable permittivities up to 220, and dielectric loss tangents less than 0.0005. A maximum applied bias field of 2.4 MV/cm resulted in a ∼55% tunability of the dielectric constant. The permittivity was independent of the measurement frequency over a wide frequency range (10 kHz–100 MHz). Above 1 MHz, losses were increasingly dominated by conductor losses of the Pt bottom electrode. Their excellent dielectric properties make BZN films attractive candidates for low-loss, medium-permittivity integrated device applications.
174 citations
TL;DR: The piezoelectric, dielectric and ferroelectric properties of lead zirconate titanate (PZT) films have been investigated as a function of Zr/Ti ratio.
Abstract: The piezoelectric, dielectric, and ferroelectric properties of highly (111)-textured, 200-nm-thick polycrystalline lead zirconate titanate (PZT) films have been investigated as a function of Zr/Ti ratio. The distinct peak in piezoelectric coefficient at the morphotropic phase boundary found in bulk PZT ceramics is not observed in thin film PZTs. Measurements of the temperature dependence of relative permittivity and the nonlinear behavior of relative permittivity and piezoelectric coefficient suggest that non-180° domain wall motion in these films is negligible, indicating that the extrinsic contribution to the room temperature permittivity is dominated by only 180° domain wall motion. The semiempirical phenomenological equation relating the piezoelectric coefficient to measured polarization and permittivity values is demonstrated to give an excellent description of the piezoelectric behavior in these films, assuming bulk electrostrictive and elastic coefficients. The small deviation between calculated and measured piezoelectric coefficients as well as the dependence of piezoelectric and polarization behavior on the external field, i.e., hysteresis loop, are suggested to be primarily due to backswitching of 180° domains.
173 citations
TL;DR: In this article, the authors present a system including a vector network analyser, horn/lens antennas, holder for grain and oilseed samples and a radiation absorbing enclosure that was used for such measurements, and the techniques and procedures followed to obtain reliable permittivity data for wheat, shelled corn (maize) and soybeans are outlined.
Abstract: Principles of dielectric property measurement by microwave free-space transmission measurements are presented, and the important sources of errors in such measurements are discussed. A system, including a vector network analyser, horn/lens antennas, holder for grain and oilseed samples and a radiation absorbing enclosure that was used for such measurements is described, and the techniques and procedures followed to obtain reliable permittivity data for wheat, shelled corn (maize) and soybeans are outlined. Data illustrating linear relationships between microwave attenuation and phase shift per unit sample thickness, each divided by the bulk density of the granular materials, and frequency and moisture content are presented graphically. The linear dependence of calculated permittivity components, dielectric constant and loss factor, on bulk density is also shown, and permittivity components for wheat, corn and soybeans are listed for reference at frequencies from 5 to 17 GHz at different densities and moisture levels at about 23 °C. Permittivity values are also listed for the same three commodities, adjusted to a medium density value through use of the Landau and Lifshitz, Looyenga dielectric mixture equation, for the total range of moisture contents at 10 GHz and at the same temperature.
160 citations
05 Oct 2003
TL;DR: Sensitivity to viscosity is more than twice that obtained for the standard quartz crystal microbalance (QCM), and sensitivity to relative permittivity and conductivity is about 1.5 times that of the QCM sensors with modified electrodes.
Abstract: Lateral field excited (LFE) AT-cut quartz acoustic wave sensors in which the electrodes are located on the reference surface have been fabricated and tested in liquid environments. The sensing surface, which is opposite to the reference surface, is free allowing the electric field of the thickness shear mode (TSM) to penetrate into the liquid. This results in increased sensitivity to both mechanical and electrical property changes of the liquid. In the present paper, several 5-MHz LFE sensors with a range of electrode spacings were exposed to liquid environments in which the viscosity, relative permittivity, and conductivity were varied. The LFE sensors demonstrate sensitivity to viscosity that is more than twice that obtained for the standard quartz crystal microbalance (QCM), and sensitivity to relative permittivity and conductivity about 1.5 times that of the QCM sensors with modified electrodes. The present results clearly indicate that the LFE sensors may have a wide range of liquid phase applications in which sensitivity is crucial.
138 citations
TL;DR: In this article, it was found that doping a nematic liquid crystal with a small amount of ferroelectric nanoparticles strongly affects the dielectric properties of the system, and that adding the particles results in a shift of the absorption bands corresponding to the rotation of liquid crystal molecules around their short axes to lower frequencies and in an increase of the amplitude and with of absorption bands, suggesting that strong interactions occur between the LC molecules and the particles, caused by the large dipole moment and high polarizability of the ferro-particles.
Abstract: It was found that doping a nematic liquid crystal (LC) with a small amount of ferroelectric nanoparticles strongly affects the dielectric properties of the system. In particular, adding the ferroelectric particles results in a shift of the absorption bands corresponding to the rotation of liquid crystal molecules around their short axes to lower frequencies and in an increase of the amplitude and with of the absorption bands. This suggests that strong interactions occur between the LC molecules and the particles, caused by the large dipole moment and high polarizability of the ferro-particles. The ferroelectric particles affect not only dielectric losses, but also dielectric permittivity of the system. Specifically, the static dielectric permittivity and the dielectric anisotropy of the suspension are more than twice that of the pure LC.
126 citations
15 Oct 2003
TL;DR: In this paper, the real part of relative permittivity perpendicular to the crystal axis and the loss tangent of LiTaO/sub 3/ over the temperature range from 15 K to room temperature at a frequency of 11.4 GHz were studied.
Abstract: Lithium tantalate single crystal is characterized by very low thermal expansion and exhibits excellent electro-optical, piezoelectric and pyroelectric properties. We have studied the real part of relative permittivity (/spl epsi//sub r/) perpendicular to the crystal axis and the loss tangent of LiTaO/sub 3/ over the temperature range from 15 K to room temperature at a frequency of 11.4 GHz. The /spl epsi//sub r/ and tan/spl delta/ were determined by measurements of the resonance frequency and the unloaded Q-factor of a TE/sub 011/ mode cylindrical cavity containing the sample under test. The permittivity of LiTaO/sub 3/ was found to change from 38.9 to 41.1 and the loss tangent increased from 1.1 /spl times/ 10/sub -4/ to 6.5 /spl times/ 10/sub -4/ over the temperature range from 15 K to 295 K. Due to the low losses and high permittivity this material can be used in many microwave applications.
123 citations
TL;DR: In this paper, the microwave permittivity of short ferromagnetic wires embedded into a dielectric matrix has been analyzed under the effect of a dc magnetic field applied to the whole composite sample.
Abstract: A type of a composite material is proposed, the microwave permittivity of which changes under the effect of a dc magnetic field applied to the whole composite sample. The composite consists of short ferromagnetic wires embedded into a dielectric matrix. A strong field dependence of the permittivity is seen in the vicinity of the antenna resonance, where the dispersion behavior can experience a transformation from a resonant spectrum to a relaxation one under the effect of the field. This permittivity behavior is due to a high sensitivity of the ac surface impedance of a ferromagnetic wire to a magnetic field, known as the magnetoimpedance (MI) effect. If the resonance-like dispersion behavior is realized, the real part of the effective permittivity can be made negative past the resonance for wire inclusion concentrations well below the percolation threshold. Applying a magnetic field, the negative peak continuously decreases as the dispersion tends to become of a relaxation type. The effective permittivity is analyzed within a one-particle approximation, by considering a wire piece as an independent scatterer and solving the scattering problem with the impedance boundary condition. A magnetic field is assumed to be applied in parallel to the wire. A new integrodifferential equation for the current distribution in a wire is obtained, which is valid for the surface impedance matrix of a general form. This work demonstrates the possibility of using the MI effect to design field-controlled composites and band-gap structures.
104 citations
TL;DR: In this article, a toroidal cross capacitor was used to measure the relative dielectric permittivity e(p,T) of He, Ar, N2, O2, CH4, C2H6, C3H8, and CO2.
Abstract: A four-ring, toroidal cross capacitor was used to measure accurately the relative dielectric permittivity e(p,T) of He, Ar, N2, O2, CH4, C2H6, C3H8, and CO2. (e is often called the “dielectric constant.”) The data are in the range from 0 to 50°C and, in many cases, extend up to 7 MPa. The accurate measurement of e(p,T) required a good understanding of the deformation of the gas-filled capacitors with applied pressure. This understanding was tested in two ways. First, the experimental values of e(p,T) for helium were compared with theoretical values. The average difference was within the noise, 〈e
expt−e
theory〉=(−0.05±0.21)×10−6, demonstrating that the four-ring cross capacitor deformed as predicted. Second, e(p,T) of argon was measured simultaneously on three isotherms using two capacitors: the four-ring capacitor, and a 16-rod cross capacitor made using different materials and a different geometry. The results for the two capacitors are completely consistent, within the specifications of the capacitance bridge. There was a small inconsistency that was equivalent to 1×10−6 of the measured capacitances, or, for argon, 3×10−5
A
e
, where A
e
is the zero-density limit of the molar polarizability ℘≡(e−1)/[(e+2)ρ].
TL;DR: In this article, a broad-band technique for measuring the relative permittivity of low-k thin films using microstrip transmission-line measurements was developed, based on measurements of the complex microstrip propagation constant and the characteristic impedance.
Abstract: Developed a broad-band technique for measuring the relative permittivity of low-k thin films using microstrip transmission-line measurements. From measurements of the complex microstrip propagation constant and the characteristic impedance, we determined the relative permittivity of thin films incorporated in microstrip lines. We present measurement results to 40 GHz for both an oxide and a bisbenzocyclobutene low-k thin film and show a variability of permittivity of approximately /spl plusmn/5% over the entire frequency range.
TL;DR: In this paper, the static permittivity of water at different temperatures was measured and its values were fitted to the same equation used for alcohols, showing that water behaves, under this point of view, like an alcohol.
TL;DR: The haematocrit dependence of the electrical parameters (relative permittivity and conductivity) of blood is investigated and the dielectric profiles are compared with those deduced from the Maxwell-Fricke theoretical model.
Abstract: We have investigated the haematocrit dependence of the electrical parameters (relative permittivity and conductivity) of blood. The measuring set-up, composed of an impedancemeter (HP 4291A), an open-ended coaxial line and a temperature controlling set, was designed for dielectric measurements in the 1 MHz to 1 GHz frequency range. Measurements were performed on ex vivo animal (cow and sheep) blood at 37 °C. The two dielectric parameters appeared to be strongly dependent on the haematocrit. The permittivity versus frequency decreases then increases when the haematocrit decreases. The conductivity increases in the whole frequency range when the haematocrit decreases. Due to the lack of comparative data on the frequency range explored, we compare the dielectric profiles with those deduced from the Maxwell–Fricke theoretical model.
TL;DR: In this article, an enhanced transmission reflection technique for the precise determination of the complex permittivity of dielectric materials partially filling the cross section of a rectangular waveguide is described.
Abstract: An enhanced transmission reflection technique for the precise determination of the complex permittivity of dielectric materials partially filling the cross section of a rectangular waveguide is described Dielectric properties are determined by an iterative procedure from two-port S-parameter measurements and a numerically generated propagation constant obtained from the analysis of a partially filled waveguide Convergence of the solution is ensured from perturbational approximations Unlike previous approaches, an uncertainty investigation is performed, taking into account all the parameters involved in the dielectric characterization Permittivity accuracy values are presented and, hence, an optimum measurement setup can be established Measurements of reference materials have been carried out to validate the method
TL;DR: In this paper, the complex permittivities of three activated carbons of diverse origin over the frequency range from 0.2 to 26 GHz were analyzed using a coaxial dielectric probe and vector network analyzer.
TL;DR: The local screening varies on length scales corresponding to first-neighbor distances, indicating that the dielectric transition is governed by the chemical grading, and Silicon-induced gap states are shown to play a minor role.
Abstract: Using a density-functional approach, we study the dielectric permittivity across interfaces at the atomic scale. Focusing on the static and high-frequency permittivities of SiO2 films on silicon, for oxide thicknesses from 12 Angstrom down to the atomic scale, we find a departure from bulk values in accord with experiment. A classical three-layer model accounts for the calculated permittivities and is supported by the microscopic polarization profile across the interface. The local screening varies on length scales corresponding to first-neighbor distances, indicating that the dielectric transition is governed by the chemical grading. Silicon-induced gap states are shown to play a minor role.
Book•
17 Jul 2003
TL;DR: In this paper, temperature pressure mixture preparation and sampling hydrocarbon reservoir fluids density speed of sound calorimetry properties of mixing relative permittivity and refractive index extreme conditions.
Abstract: Selected papers: temperature pressure mixture preparation and sampling hydrocarbon reservoir fluids density speed of sound calorimetry properties of mixing relative permittivity and refractive index extreme conditions.
TL;DR: The ceramic Ba8ZnTa6O6O24 has been synthesized in isolation and its dielectric and crystallographic properties characterized in this article, with a high unloaded quality factor Qu=20Ê800 at 328 GHz, high relative permittivity er=29 and a temperature coefficient of resonant frequency τf=294 ppm/°C.
Abstract: The ceramic Ba8ZnTa6O24 has been synthesized in isolation and its dielectric and crystallographic properties characterized The material affords excellent dielectric properties, with a high unloaded quality factor Qu=20 800 at 328 GHz, high relative permittivity er=29 and a temperature coefficient of resonant frequency τf=294 ppm/°C The crystal structure adopted is complex, comprising mixed cubic and hexagonal perovskite subunits, and contains cation vacancies on the octahedral sites A second phase with a closely related structure is identified, demonstrating the existence of a family of materials This structural complexity offers diverse opportunities for substitutions calculated to enhance the figures of merit reported
TL;DR: In this article, the capacitance and complex admittance of BaTiO3(BTO)/SrTiOO3 (STO) superlattices on STO substrates were measured at 1-110 MHz.
Abstract: Artificial BaTiO3(BTO)/SrTiO3(STO) superlattices on STO substrates were fabricated by the molecular beam epitaxy process. The capacitance and the complex admittance of superlattices with interdigital electrode structures were measured at 1–110 MHz. The dielectric properties of the superlattices were evaluated by the electromagnetic analysis. It was found that the dielectric permittivity changed with the structure of superlattices and the highest permittivity of 33 000 was obtained for [(BTO)10/(STO)10]4 superlattice from 1 to 110 MHz.
TL;DR: In this paper, the dielectric permittivity of Na0.80K0.20NbO3 ceramic was investigated by impedance spectroscopy in the frequency range 5 Hz to 13 MHz.
TL;DR: In this article, a new composite medium that possesses simultaneously negative permittivity and permeability in the microwave wavelength range is proposed, which is composed of evanescent waveguide structures responsible for the negative permitivity, with embedded cylindrical elements of a one-dimensional chiral medium accounting for negative permeability.
Abstract: A new composite medium that possesses simultaneously negative permittivity and permeability in the microwave wavelength range is proposed. The medium is composed of evanescent waveguide structures responsible for the negative permittivity, with embedded cylindrical elements of a one-dimensional chiral medium accounting for the negative permeability. The evanescent waveguide structures exhibit blooming and antiresonances in the reflection coefficient.
Patent•
15 Jul 2003
TL;DR: In this paper, the authors proposed a piezoelectric ceramic composition which is lead-free and has high dielectric characteristics, and is excellent in, especially, at least one of a piezo-lectric charge constant d 31, a relative permittivity, a Dielectric loss, and a Curie temperature Tc.
Abstract: PROBLEM TO BE SOLVED: To provide a piezoelectric ceramic composition which is lead-free, has high piezoelectric characteristics, and high dielectric characteristics, and is excellent in, especially, at least one of a piezoelectric charge constant d 31 , a relative permittivity, a dielectric loss, and a Curie temperature Tc, to provide its production method, and to provide a piezoelectric element and a dielectric element using the piezoelectric ceramic composition. SOLUTION: The piezoelectric ceramic composition mainly consists of a compound represented by the formula: aLi x (K 1-y Na y ) 1-x }(Nb 1-z-w Ta z Sb w )O 3 (wherein x, y, z, and w are in the ranges: 0≤x≤0.2, 0≤y≤1, 0 COPYRIGHT: (C)2004,JPO&NCIPI
TL;DR: In this article, an overview of the homogenization of anisotropic materials at fixed frequency using the concept of two-scaled convergence is presented, and a comparison between the exact homogenisation method presented in this paper and the traditional mixture formulae which are based on physical arguments is made.
Abstract: This paper contains an overview of the homogenization of anisotropic materials at fixed frequency using the concept of two-scaled convergence. The homogenized electric and magnetic parameters, the relative permittivity, and the relative permeability are found by suitable averages of the solution of a local problem in the unit cell. A comparison between the exact homogenization method presented in this paper and the traditional mixture formulae, which are based on physical arguments, is made.
TL;DR: In this paper, an experimental study on the dipole resonance of long highconducting fibers embedded in an inhomogeneous composite sheet was conducted, and it was shown that the resonance frequency is determined completely by the thickness and permittivity of the composite sheet, in particular, with the anisotropy of the permittivities.
Abstract: An experimental study on the dipole resonance of long high-conducting fibers embedded in an inhomogeneous composite sheet was conducted. The location of the resonance characterizes the effect of the inhomogeneous environment on the electromagnetic response of the fibers. It is shown that the resonance frequency is determined completely by the thickness and permittivity of the composite sheet, in particular, with the anisotropy of the permittivity. No effect due to inhomogeneity of the environment is observed. This is in disagreement with the scale-dependent effective medium theory (SDEMT) that is conventionally exploited to model the permittivity of fiber-filled composites, because this theory shows that the response of the fibers depends on the inhomogeneity scale of the environment. Therefore, although the SDEMT provides qualitative agreement with the observed behavior of fiber-filled composites, it must be further improved to obtain better quantitative agreement with experimental data. The experimental data obtained can also be useful to the development of microwave dielectrics with complex frequency dispersion behavior, which are necessary for many microwave applications.
Patent•
19 Nov 2003TL;DR: In this paper, a slot-fed microstrip patch antenna (200) is described, which includes an electrically conducting ground plane (208), the ground plane having at least one coupling slot and at least a first patch radiator (209).
Abstract: A slot fed microstrip patch antenna (200) includes an electrically conducting ground plane (208), the ground plane (208) having at least one coupling slot (206) and at least a first patch radiator (209). An antenna dielectric substrate material (205) is disposed between the ground plane (208) and the first patch radiator (209), wherein at least a portion of the antenna dielectric (210) includes magnetic particles (214). A feed dielectric substrate (212) is disposed between a feed line (217) and the ground plane (208). Magnetic particles can also be used in the feed line (217) dielectric. Patch antennas according to the invention can be of a reduced size through use of high relative permittivity dielectric substrate portions, yet still be efficient through use of dielectrics including magnetic particles which permit impedance matching of dielectric medium interfaces, such as the feed line (217) into the slot (206).
10 Apr 2003
TL;DR: In this paper, a detailed overview of precise resonant measurement methods for complex permittivity determination of low and medium loss dielectrics is presented, including split post dielectric resonator (SPDR), TE 0, 1, 1 resonator, TE 0, 1, δ mode dielector, and whispering gallery mode resonators.
Abstract: Overview of precise resonant measurement methods for complex permittivity determination of low and medium loss dielectrics is presented. The following techniques are discussed: split post dielectric resonator (SPDR), TE 0 1 1 resonator, TE 0 1 δ mode dielectric resonator, and whispering gallery mode resonators (WGMR). Applications of split post dielectric resonators (SPDR) for measurements of specific materials like ferroelectrics and thin laminar materials are highlighted. It is shown that TE 0 1 δ mode dielectric resonator technique is one of the most accurate for permittivity, dielectric loss tangent and thermal coefficients of permittivity measurements of low and medium loss dielectrics having arbitrary permittivity value. Precise measurements of low permittivity dielectrics require spurious modes analysis and proper choice of sample size and its aspect ratio. Conductor and radiation loss limits are discussed for open and closed whispering gallery mode resonators.
TL;DR: Application of a quasi-optical apparatus in the determination of the constituent parameters of materials is presented and good agreement was observed between manufacturer specifications and measurements after application of the correction terms.
Abstract: The application of a quasi-optical apparatus in the determination of the relative permittivity of low-loss dielectric materials is presented in this paper. A description of the measurement system and its components is provided. Correction terms are introduced to remove errors due to the position tolerance of the sample and the calibration procedure. Two numerical methods are used to determine the relative permittivity from reflection and transmission coefficients. Good agreement was observed between corrected results obtained with the quasi-optical measurement system and measurements performed by an independent standards testing organization.
08 Jun 2003
TL;DR: In this paper, an Artificial dielectric disk resonators are created to excite the TE/sub 01/spl delta mode selectively, aligning the rectangular metal patterns along the direction of the mode electric field lines.
Abstract: Artificial dielectrics of very high equivalent permittivity are designed and fabricated by use of a patterned PCB printed circuit board. Rectangular metal patterns are etched out to attain as big a capacitance with each other as possible but as small a current as possible, which is important in order to realize large permittivity and small loss, respectively. Artificial dielectric disk resonators are created to excite the TE/sub 01/spl delta// mode selectively, aligning the rectangular metal patterns along the direction of the mode electric field lines. Thus, a miniaturized BPF with superior spurious characteristics is fabricated using three disk resonators.
TL;DR: In this article, the dielectric properties of perovskite-type BaTiO3-based ceramics have been studied at microwave frequencies, and the results are a relative permittivity, epsilon(r), of similar to74 and a quality factor, Q(.)f(r).
Abstract: High-permittivity and low-loss ceramics with composition BaTi0.92Ga0.08O2.96 have been prepared in the BaO-Ga2O3TiO2 system using the mixed-oxide route. This compound forms as the hexagonal polymorph (6H) of BaTiO3 with the space group P6(3)/mmc. The dielectric properties of dense ceramics have been studied, at microwave frequencies, with the ceramics fired at 1450degreesC under flowing oxygen gas; the results are a relative permittivity, epsilon(r), of similar to74 and a quality factor, Q(.)f(r), of similar to7815 at 5.5 GHz. The quality factor is strongly influenced by the sintering conditions (temperature and atmosphere), whereas the relative permittivity is not influenced significantly by ceramic processing for pellets greater than or equal to93% of the theoretical X-ray density. To our knowledge, this is the first report of microwave dielectric resonance in a perovskite-type BaTiO3-based ceramic.