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Electrodeless Measurement Technique of Complex Dielectric Permittivity of High-K Dielectric Films in the Millimeter Wavelength Range

Electrodeless Measurement Technique of Complex Dielectric Permittivity of High-K Dielectric Films in the Millimeter Wavelength Range

The schematic of OR with the sample located on the flat mirror is presented in Fig. 1. The sample is a two-layer structure — substrate/high K-film. The microwave properties of substrate are known from handbooks or on the base of preliminary measurement of the substrate without film in open resonator. Installation of the sample changes the resonance frequency and to restore the mode of measurements the frequency shift is compensated by the movement of the plane mirror at a distance p . Theoretical approach of measurements is based on results of theory developed by [13] for E- and H-field distribution in open resonator with one layer dielectric. Relationship between the resonance frequency
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Study of Effective Dielectric Permittivity and Capacitance for Finite Dielectric Thickness Coplanar Waveguide

Study of Effective Dielectric Permittivity and Capacitance for Finite Dielectric Thickness Coplanar Waveguide

Alumina is the ceramic form of sapphire. It has balanced properties of insulation, thermal conductivity and breaking strength. It is usually available in white color having dielectric constant varying from 9.5 to 10 with loss tangent tanδ = 0.0002. Its unique property is surface roughness and excellent adhesion with a thin film and thick film metallization due to fine particles. Various advantages of Alumina are: Physical and chemical properties are stable even at very high temperatures, High Mechanical strength, Good in insulation properties, Less porous with good smoothness. Gold metallization is frequently used with alumina. Usually a very thin adhesion layer is used between alumina and gold.
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Dielectric and Microwave Properties of Natural Rubber Based Nanocomposites Containing Graphene

Dielectric and Microwave Properties of Natural Rubber Based Nanocomposites Containing Graphene

The data about graphene influence on the microwave properties of the elastomeric composites are very scarce. Y. Chen et al. used functionalized graphene-epoxy com- posites as lightweight shielding materials for electro- magnetic radiation [12]. I. M. De Rosa and coworkers have a wide expertise in the design of micro/nanocom- posites based on carbon fibers and carbon nanotubes, for the realization of high performing radar absorbing screens, with tailored properties [13-15]. In a recent paper [16], the authors have accomplished a Salisbury screen, that consists of three layers. The second layer (the spacer) is a low-loss-tangent nanocomposite based on a Bisphenol-A based epoxy resin filled with GNPs at 0, 5 and 1 wt% [16]. The real and imaginary parts of the complex effec- tive permittivity within the 8 - 18 GHz range of the nano- composite filled with GNPs have been shown. It has been observed that the real part of the effective permit- tivity is nearly constant.
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Material-Loaded High Q-Factor Slot Resonator and Measurement of Relative Permittivity

Material-Loaded High Q-Factor Slot Resonator and Measurement of Relative Permittivity

The geometric configuration of the proposed ground plane slot resonator is shown in Fig. 1. The structure consists of a 50 Ω microstrip line on the top layer and a rectangular slot is etched in the ground plane of substrate. Two metallic plates forming a parallel plate capacitor is soldered with the ground plane across the ground slot. The low loss dielectric material could be placed between two metallic plates to increase the loading capacitance. The maximum electric field in the slot is at the centre of the slot; where parallel plates are soldered.

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Dielectric and Microwave Properties of Natural Rubber Based Composites Effect by Activated Carbons

Dielectric and Microwave Properties of Natural Rubber Based Composites Effect by Activated Carbons

Through equations available in the literature8, we can see that the combination of the magnetic permeability and the permittivity of the absorbing composite satisfying the impedance matching condition is the key to producing a high-performance microwave absorber. Specifically, for a single layer of absorber backed by a PEC [perfect electric conductor] the reflection loss and the attenuation constant are dependent on complex magnetic permeability, permittivity, and frequency. If we consider diamagnetic carbonaceous materials, microwave absorbers are due to dielectric losses. In the case of a dielectric absorbent, assuming that µ=1 - j0, the maximum reflection loss and the attenuation coefficient depend on real and imaginary part of permittivity, dielectric loss angle tangents at a given frequency8. This is why to explain the effect observed we investigated the dielectric properties of the composites studied.
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Simulation of floating potentials in industrial applications by boundary element methods

Simulation of floating potentials in industrial applications by boundary element methods

We consider the electrostatic field computations with floating potentials in a multi-dielectric setting. A floating potential is an unknown equipotential value associated with an isolated perfect electric conductor, where the flux through the surface is zero. The floating potentials can be integrated into the formulations directly or can be approximated by a dielectric medium with high permittivity. We apply boundary integral equations for the solution of the electrostatic field problem. In particular, an indirect single layer potential ansatz and a direct formulation based on the Steklov-Poincaré interface equation are considered. All these approaches are discussed in detail and compared for several examples including some industrial applications. In particular, we will demonstrate that the formulations involving constraints are vastly superior to the penalized formulations with high permittivity, which are widely used in practice.
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Left-Handed Materials Based on Crystal Lattice Vibration

Left-Handed Materials Based on Crystal Lattice Vibration

As expected from Mie theory, the dielectric sphere is equivalent to a magnetic dipole near the magnetic resonance mode and the magnetic field is mainly localized in the sphere as shown in Figure 4(a). However, when the CTO rods are placed beside the dielectric sphere, the magnetic field distribution is changed. The magnetic field in the gap enhances greatly while that in the sphere decreases as the rod approaches the dielectric sphere. When the distance between the rod and the sphere is reduced to zero, the intensity of the magnetic resonance even decreases by about 15% from about 5.7×10 4 A/m to
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Structure and dielectric properties of sol gel processed Ba (Fe1/2Nb1/2) O3 ceramics

Structure and dielectric properties of sol gel processed Ba (Fe1/2Nb1/2) O3 ceramics

In this work, barium iron niobate, Ba (Fe1/2Nb1/2) O3 powder has been successfully perovskite structure of BFN was followed ray diffraction (XRD), and has shown a crystallite size at a nanometric scale. The pure perovskite phase was obtained at relatively low temperature (900°C /8 h) compared to the state reaction. Moreover, dielectric measurements showed strong relaxation and diffuse phenomena, and a maximum of the dielectric permittivity at a temperature lower than those reported in the literature, together with resonance phenomenon at high frequency values. Impedance parameters were extracted from the permittivity analysis and enabled us in particular, to determine the
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Radar Scatter from Layered Media and Rough Surfaces

Radar Scatter from Layered Media and Rough Surfaces

There have been numerous approaches to model electromagnetic (EM) backscatter from rough surfaces and from horizontally stratified media, but these typically involve assumptions that limit the overall solutions to the point that the phenomena being modeled are not physically realizable. Lord Rayleigh [1] developed the perturbation method to study the reflection of acoustic waves from a sinusoidal surface and this was first extended to electromagnetic waves by Rice [2]. Rice considered static 2D rough surfaces that could be expressed as a Fourier Series with the series coefficients as random variables. The analysis was completed to second order for scatter from a perfectly conducting surface and a horizontally- polarized wave on a rough dielectric surface. Wait [3] considered reflection of a vertically-polarized EM wave from a 2D periodic surface using the Leontovich boundary conditions and derived results to second order. Barrick [4, 5] was interested in radar propagation across the ocean and considered the wave as being guided by a rough, conductive surface. The scattered field was limited to the component traveling away from the surface and multiple scattering was not included in the analysis. These results were extended to all spectral orders of scattering by Rosich and Wait [6]. Rodriguez and Kim [7] developed a unified perturbation expansion that reduced to Rice’s results when the same assumptions are made, but the second order cross sections deteriorate as incidence angle or surface height increases. Perturbation methods are one of the most common approaches for modeling backscatter from rough surfaces. However they are only valid when the amplitude of surface roughness is much smaller than the radar wavelength and some implementations of the technique assume plane wave incidence.
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Dielectric Behaviour of Pure and Dye Doped Nematic Liquid Crystal BKS/B07

Dielectric Behaviour of Pure and Dye Doped Nematic Liquid Crystal BKS/B07

The dielectric parameters  and  have been meas- ured for a nematic liquid crystal BKS/B07 in the fre- quency range of 1 kHz to 10MHz for the temperature range of 70˚C to 135˚C. Figure 3 and Figure 4 represent typical frequency dependence spectra of the real and imaginary part of the dielectric permittivity measured for nematic sample BKS/B07 and dye doped mixtures 1 and 2. The dielectric permittivity is found to be either con- stant or to decrease as the frequency increases [17-22] for pure sample. Lower values of  at higher frequency suggest that the molecules rotate about their long mo- lecular axis [23]. The behaviour of  for the dye based mixtures 1 and 2 is similar to that of pure sample but the values of dielectric constants are higher in comparison to the corresponding values of pure sample.
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Optical, dielectric and magnetic properties of

Optical, dielectric and magnetic properties of

effect of Nd 3+ doping on the dielectric permittivity and magnetization in the wide frequency range.. 21.[r]

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Kinetic features of the oxidation of secondary alcohol by polymer   supported chromic acid

Kinetic features of the oxidation of secondary alcohol by polymer supported chromic acid

Effect of variation of dielectric permittivity of the medium on the reaction rate It was found that as the dielectric constant of the medium increased, this including r* < r [Where r* an[r]

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Measurable Dielectric Permittivity Range for TE and TM Modes in a Shielded Dielectric Resonator

Measurable Dielectric Permittivity Range for TE and TM Modes in a Shielded Dielectric Resonator

Hertzian potentials have been used to solve different electromagnetic problems: in the study of the properties of aperture array systems [1], non-linear waveguides [2], Green’s functions for multilayered media [3] and electromagnetic wave interaction with nanodevices [4]. They have also been applied for the determination of TE and TM modes of circular cylindrical cavities using magnetic-type and electric-type Hertzian potentials res- pectively [5]. Figure 1 shows the case of a cylindrical dielectric resonator enclosed by a metal shield, where b is the radius of the outer cylinder, a is the inner resonator radius and d is the height (length of the structure). The configuration can be regarded as a cylindrical waveguide enclosing a central sample of radius a, and terminated by perfectly conducting planes. The general solution for the axial E field in TM modes was discussed in [6], proposing a general solution for the axial E field for TM modes.
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Complex Permittivity Estimation for Each Layer in a BI-Layer Dielectric Material at Ku-Band Frequencies

Complex Permittivity Estimation for Each Layer in a BI-Layer Dielectric Material at Ku-Band Frequencies

Abstract—In this paper, a new measurement method is proposed to estimate the complex permittivity for each layer in a bi-layer dielectric material using a Ku-band rectangular waveguide WR62. The S ij - parameters at the reference planes in the rectangular waveguide loaded by a bi-layer material sample are measured as a function of frequency using the E8634A Network Analyzer. Also, by applying the transmission lines theory, the expressions for these parameters as a function of complex permittivity of each layer are calculated. The Nelder-Mead algorithm is then used to estimate the complex permittivity of each layer by matching the measured and calculated the S ij -parameters. This method has been
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Dielectric Slab Mode Antenna for Integrated Millimeter wave Transceiver Front ends

Dielectric Slab Mode Antenna for Integrated Millimeter wave Transceiver Front ends

Among the most important parts of a wireless system is the antenna, since it strongly influences the overall receiver sensitivity and the link budget. In the near future, wireless transmission for consumer products will also happen at much higher frequencies than nowadays, i.e. in the millimeter wave (mm-wave) frequency range. This is required to achieve very fast data exchange and HD video streaming between all kinds of consumer products [1-3]. High radiation efficiency is particularly important due to significant free-space loss, very limited battery capacity in portable devices and consequential low transmit power levels, which
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Effect of local A site strain on dipole stability in A6GaNb9O30 (A = Ba, Sr, Ca) tetragonal tungsten bronze relaxor dielectrics

Effect of local A site strain on dipole stability in A6GaNb9O30 (A = Ba, Sr, Ca) tetragonal tungsten bronze relaxor dielectrics

size variance. The variance provides a measure of local struc- ture and so it is clear that local structure plays a significant role in the dielectric response. Such information is not avail- able via conventional Rietveld analysis of di ff raction data and probes of local structure are required. Nevertheless, it appears that variance may be a useful metric to guide the tuning of properties in TTBs and could be extended to other structure types which contain perovskite units such as Ruddlesen- Popper and Dion-Jacobsen phases.

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Genetic Algorithm Optimization for Microstrip Patch Antenna Miniaturization

Genetic Algorithm Optimization for Microstrip Patch Antenna Miniaturization

Recently, several methods have been used to optimize patch antennas with varying success, such as using a dielectric substrate of high permittivity [1], Defected Microstrip Structure (DMS) [2], Defected Ground Structure (DGS) at the ground plane [3] or a combination of them, and various existing optimization algorithms such as particle swarm optimization (PSO) [4] and genetic algorithm [5–7]. The latter is one of the global optimization algorithms that have been used widely in the past by antenna designers for the optimization of the patch shape and size in order to achieve better overall performance of the antenna.
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Uncertainty Minimization in Permittivity Measurements in Shielded Dielectric Resonators

Uncertainty Minimization in Permittivity Measurements in Shielded Dielectric Resonators

Continuing with our previous work [1] in this paper, we present an effective method that minimizes the uncertainty in the measurement of the real dielectric permittivity of a material. As we indicated previously, the method is valid only for low loss materials in view of the nature of the exact relations between permittivity, sample and cavity dimensions, measured resonant frequency and the unloaded Q- factor for the resonant structures. Resonant methods are the preferred technique in dielectric permittivity measurements over non-resonant measurements [2], in view to their higher accuracy and sensitivity. Although, recent papers have discussed the problems associated to the estimation of uncertainty in the measurement of dielectric permittivity of materials, but only a few have proposed a systematic methodology for the reduction of the uncertainty associated to the measurement of the dielectric permittivity using resonant cavities [3].
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Dielectric permittivity modulation of liquid crystals for microwave applications

Dielectric permittivity modulation of liquid crystals for microwave applications

visually due to the use of metal electrodes in our system. The tuning voltage in our measurement system is limited to 40 Vp-p and the cell thickness is about 28µm. The resulting field strength of 1.43 V/µm may not be high enough to achieve maximum tunability. The other reason could be the possibility of affecting accuracies at the edge of measurement frequency ranges. The data at 1GHz by Weil el. al. was measured at the edge of their measurement frequency range (0.1-1 GHz), whereas it was in the middle in our case (frequency range: 0.01-6 GHz).

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Effect of Aluminum Nano Particles on  Microrelief and Dielectric Properties  of PE+TlInSe2 Composite Materials

Effect of Aluminum Nano Particles on Microrelief and Dielectric Properties of PE+TlInSe2 Composite Materials

determined by contacts between Al nano-particles. At the boundaries of clusters in the alternating electric field an accumulation and redistribution of free charges occurs, which changes the initial internal electric field. It is known that at low frequencies, internal electric fields are distributed accordingly conductivity and high frequen- cies—respectively the dielectric permittivity. Therefore, the decrease ε '' and tg δ with increasing content of alu- minum nano-particles can be explained by the appearance of a relatively strong internal field in semiconductors and nano-clusters.
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