Measurement of the dielectric properties of materials at RF and microwave frequencies

Clarke, Bob

doi:10.1049/pbel012e_ch18

Cited by 35 publications

(63 citation statements)

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“…The rings were precisely fabricated with flat and parallel edges and tight fit in the holder to ensure the single-mode propagation [19]. The materials' complex effective permittivity (ε * eff = ε − jε ) and permeability (μ * eff = μ − jμ ) were extracted by the Nicolson-Ross-Weir algorithm [20], [21] and by implementing the airgap and position corrections [19], [22]. The dc bulk conductivity, σ DC , of the disk samples was measured at 500 V through the two-probe method with an insulation-resistance test instrument (Metriso C-GB, Gossen Metrawatt).…”

Section: Methodsmentioning

confidence: 99%

Hybrid Nanocomposites With Organoclay and Carbon-Based Fillers for EMI Suppression

Stergiou

Stimoniaris²,

Delides³

2015

IEEE Trans. Electromagn. Compat.

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The reinforcing role of clays in modern nanocomposites raises the question upon potential synergies with other fillers, in terms of their microwave properties and performance. To this effect, hybrid, multiphase composites are fabricated to comprise organomodified nanoclay (NC) and multiwalled carbon nanotubes (MWCNTs) or carbon black nanoparticles (CB) at varying concentrations in epoxy resin matrix (ER). The performed electromagnetic (EM) characterization in the 2-18-GHz band reveals that NC generally degrades the effective permittivity ε * eff of the NC/CB/epoxy composites, whereas for 2wt% NC a local ε * eff maximum is observed in the NC/MWCNT/epoxy system. This divergent impact of NC is attributed to different microstructural features affecting the dipolar dielectric polarization. Finally, the composites with high ε * eff contribute to the miniaturization of reflection reducing and shielding panels, since the respective return and transmission loss are found to be dominated by the destructive interference mechanism. For both topologies, the composite loaded with 2wt% NC and 0.5wt% MWCNT is evaluated as the most effective in attenuating the EM waves. Through the analysis of the microwave dielectric properties and the shielding mechanisms, the material design objectives emerge along with the potential of NC/carbon nanotubes composites for suppression of EM interference.

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Section: Methodsmentioning

confidence: 99%

Hybrid Nanocomposites With Organoclay and Carbon-Based Fillers for EMI Suppression

Stergiou

Stimoniaris²,

Delides³

2015

IEEE Trans. Electromagn. Compat.

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“…The form of the tooling materials dictated how their dielectric properties were measured. Laminar materials of thicknesses < 2 mm required the use of a mode cavity method (Split-Post Dielectric Resonator (SPDR)), whereas non-laminar materials were measured using a resonance cavity perturbation method, as they could be contained within a sample tube [29] .…”

Section: Dielectric Propertiesmentioning

confidence: 99%

Tooling materials compatible with carbon fibre composites in a microwave environment

Nuhiji

Swait

Bower

et al. 2019

Composites Part B: Engineering

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Although metals are the most commonly used tooling materials to cure composites, they do not provide optimal results in a microwave environment. Following a selection process based on the properties of the materials, an alternative tooling material in carbon fibre reinforced plastic (CFRP) was successfully utilised to cure CFRP panels in laboratory and industrial microwaves. The conductive carbon fibres in the tool facilitated the fast heat transfer across the part. Other tooling materials including a glass fibre cyanate ester prepreg and tooling board were trialled, although the latter exhibited damage during cure. These advantages demonstrate that the CFRP tool is a compatible material that can be used when microwave curing composites.

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“…En cuanto a la adquisición de los datos experimentales, en general existe una gran oferta de equipamiento y técnicas para mediciones dieléctricas de laboratorio. Una excelente revisión de las técnicas para RF y Microondas se puede encontrar en la referencia [12]. Otro material interesante a modo de introducción es la nota de aplicación de Agilent [61].…”

Section: Métodos De Mediciónunclassified

Identificación de sistemas

Irastorza¹

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En esta tesis consideramos el desarrollo de dos tipos de experimentos no destructivos sobre muestras de hueso: experimentos de ultrasonido y, principalmente, mediciones dieléctricas. La no invasividad o no destructividad constituye una cualidad importante en estudios experimentales sobre tejidos biol´ogicos por varias razones. Entre estas podemos mencionar la posibilidad de reutilizar las mismas muestras para varias pruebas, y también la posibilidad de trabajar cerca de las condiciones ﬁsiológicas con poco esfuerzo en lo referente a la preparación de las muestras. A esto habría que sumar la potencialidad de este tipo de mediciones para diagnósticos médicos. Por otro lado, debido al rango de frecuencias utilizado en las mediciones dieléctricas, la radiación electromagnética aplicada es del tipo no ionizante.

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Measurement of the dielectric properties of materials at RF and microwave frequencies

Cited by 35 publications

References 0 publications

Hybrid Nanocomposites With Organoclay and Carbon-Based Fillers for EMI Suppression

Hybrid Nanocomposites With Organoclay and Carbon-Based Fillers for EMI Suppression

Tooling materials compatible with carbon fibre composites in a microwave environment

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