Microwave Electronics

Chen, L. F.; Ong, C. K.; Neo, C. P.; Varadan, Vasundara V.; Varadan, V. K.

doi:10.1002/0470020466

Cited by 1,120 publications

(460 citation statements)

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“…It may represent an actual conductivity caused by migrating charge carriers, and it may also refer to lost energy associated with the dispersion of e¢. 39 The AC conductivity, s AC , must be distinguished from its DC value, s DC , because it may include permanent dipole orientation losses, as well as frequency-dependent space charge polarization-controlled carrier migration processes, which do not arise under DC conditions. It is shown that for all of these composites at low frequencies, the conductivity is almost constant, showing the AC conductivity characteristic of disordered materials.…”

Section: Electrical and Dielectric Propertiesmentioning

confidence: 99%

Polyaniline-doped benzene sulfonic acid/epoxy resin composites: structural, morphological, thermal and dielectric behaviors

Belaabed

Lamouri

Naar

et al. 2010

Polym J

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Conducting polymer composites, which are simply physical mixtures of an insulating polymer matrix and intrinsically conducting polymers, are promising new materials for various applications such as antistatic coatings, shielding and electromagnetic absorbers. In this context, a novel conducting composite was successfully produced. It is based on epoxy resin and polyaniline (PANI) doped in benzene sulfonic acid, which was used as conducting filler. The effect of PANI loading levels on the structural, morphological, thermal, electrical and dielectric properties was explored using techniques, such as Raman, Fourier transform infrared and ultraviolet-visible-NIR spectroscopy, X-ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry. The electrical behavior and morphology of the synthesized PANI revealed disorder and defects. In addition, as the applied voltage is increased, the current through the sample increases rapidly. The conductivity and dielectric properties were also investigated at room temperature in the frequency range of 1 MHz-1 GHz. The dielectric constant was shown to increase with increased loading at low frequencies and then decreases rapidly, reaching a constant value at higher frequencies. In addition, the AC conductivity of the prepared composites increases with the addition of PANI and is higher at high frequencies. Furthermore, the stability of the composites was found to be influenced by increasing the amount of PANI filler in the matrix.

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Section: Electrical and Dielectric Propertiesmentioning

confidence: 99%

Polyaniline-doped benzene sulfonic acid/epoxy resin composites: structural, morphological, thermal and dielectric behaviors

Belaabed

Lamouri

Naar

et al. 2010

Polym J

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“…The Nicolson-Ross-Weir (NRW) method has, for more than forty years, been a standard technique for measuring the permittivity and permeability of homogeneous, isotropic materials [1][2][3][4]. The method is robust to most common sources of experimental error, and utilizes closed form expressions for the desired material properties that are computed from measured S-parameters.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Nicolson-Ross-Weir Method for Characterizing the Electromagnetic Properties of Engineered Materials

Rothwell¹,

Frasch²,

Ellison³

et al. 2016

PIER

143

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Abstract-A method for predicting the behavior of the permittivity and permeability of an engineered material by examining the measured S-parameters of a material sample is devised, assuming that the sample is lossless and symmetric. The S-parameter conditions under which the material parameters extracted using the Nicolson-Ross-Weir method may be associated with a lossless homogeneous material are described. Also, the relationship between the signs of the real and imaginary parts of the permittivity and permeability are determined, both when the extracted material parameters are real and when they are complex. In particular, the conditions under which metamaterials exhibit double-negative properties may be predicted from the S-parameters of a metamaterial sample. The relationships between material characteristics and the S-parameters should prove useful when synthesizing materials to have certain desired properties. Examples, both from experiment and simulation, demonstrate that the relationships may be used to understand the behavior of several different categories of engineered materials, even when the materials have appreciable loss.

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“…Microwave engineering requires precise knowledge on electromagnetic properties of materials at microwave frequencies since microwave communications are playing more and more important roles in military, industrial, and civilian life [1][2][3]. For these reasons, various microwave techniques, each with its unique advantages and constraints [1], are introduced to characterize the electrical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

“…For these reasons, various microwave techniques, each with its unique advantages and constraints [1], are introduced to characterize the electrical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

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A Simple Approach for Evaluating the Reciprocity of Materials Without Using Any Calibration Standard

Hasar¹,

Şimşek²

2009

PIER

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Abstract-A simple approach for evaluation of the reciprocity of materials using raw scattering parameter measurements is proposed. This approach not only reduces the overall measurement time but also eliminates the need for calibrating the measurement system since it uses calibration-independent measurements. We have derived a metric function for reflecting and nonreflecting cells, which are used to house the sample under test. This function does not depend on electrical properties of materials and their lengths, and whether the cell is reflecting. We have also investigated the effects of the sample length and air pockets between sample external surfaces and cell inner walls on the performance of the evaluation of sample reciprocity.

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Microwave Electronics

Cited by 1,120 publications

References 0 publications

Polyaniline-doped benzene sulfonic acid/epoxy resin composites: structural, morphological, thermal and dielectric behaviors

Polyaniline-doped benzene sulfonic acid/epoxy resin composites: structural, morphological, thermal and dielectric behaviors

Analysis of the Nicolson-Ross-Weir Method for Characterizing the Electromagnetic Properties of Engineered Materials

A Simple Approach for Evaluating the Reciprocity of Materials Without Using Any Calibration Standard

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