Electromagnetic Properties of Syntactic Foam Composites

AbstractA numerical model based upon renormalized effective medium theory will be described. The model successfully predicts the frequency dispersive permittivity of finite thickness dielectric/ conducting microsphere composites, electrically lossy syntactic foams, where the conducting particulates have volumetric fraction of 0 to 50%. The composites display unique frequency dispersions which are associated with the composite dimensionality and fractal-like sphere surface morphology. Theory and measurement show the composites have critical volume fractions which can be 20% above theoretical values for conducting spheres, i.e 27-–31% and the frequency dispersion of the composite permittivity can be varied by controlling the nanoscale surface morphology and composite thickness. Supporting permittivity measurements in the frequency range of 1–100 GHz will be presented.

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Effective-medium theory for granular high-Tcsuperconductors-electromagnetic properties in the microwave region

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/2/12/010 ◽

1990 ◽

Vol 2 (12) ◽

pp. 2867-2871 ◽

Cited By ~ 2

Author(s):

T C Choy ◽

A M Stoneham

Keyword(s):

Effective Medium Theory ◽

Effective Medium ◽

Electromagnetic Properties ◽

Medium Theory ◽

Microwave Region

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Design of Sievenpiper HIS for use in planar broadband antennas by means of effective medium theory

Advances in Radio Science ◽

10.5194/ars-5-87-2007 ◽

2007 ◽

Vol 5 ◽

pp. 87-94 ◽

Cited By ~ 4

Author(s):

S.K. Hampel ◽

O. Schmitz ◽

O. Klemp ◽

H. Eul

Keyword(s):

Electromagnetic Compatibility ◽

Effective Medium Theory ◽

Electromagnetic Properties ◽

Medium Theory ◽

Broadband Antennas ◽

Simulation Tools ◽

Electromagnetic Structure ◽

High Impedance ◽

Data Rates ◽

Increasing Demand

Abstract. The claim for multistandard operating handsets of small physical size as well as the ever increasing demand for higher data rates require new broadband operating antennas. Because of the widespread use of especially planar broadband antennas a lot of factors influencing the characteristic antenna parameters have to be regarded. Furthermore, aspects regarding the electromagnetic compatibility inside the handheld as well as the protection of biological systems, e.g. the user of a mobilephone, have to be payed attention to. An electromagnetic structure which allows for protection by means of shielding as well as enhances the antennas efficiency by providing unique electromagnetic properties are the so called Sievenpiper High Impedance Surfaces (HIS) invented by Sievenpiper (1999). This paper will present the theory and the well known design equations for those structures. An investigation by means of simulation tools and measurement setups will be done to approve the accuracy of the theoretical results. Here measurement results of the impedance and radiation properties of a planar log.-per. four-arm antenna equiped in conjunction with a fabricated prototype Sievenpiper HIS will be presented.

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Effective Medium Theory of Metamaterials and Metasurfaces

10.1017/9781108872386 ◽

2021 ◽

Author(s):

Wei Xiang Jiang ◽

Zhong Lei Mei ◽

Tie Jun Cui

Keyword(s):

Negative Refraction ◽

Effective Medium Theory ◽

Access Point ◽

Parameter Extraction ◽

Effective Medium ◽

Electromagnetic Properties ◽

Medium Theory ◽

Real World Applications ◽

Potential Applications ◽

Physical Phenomena

Metamaterials, including their two-dimensional counterparts, are composed of subwavelength-scale artificial particles. These materials have novel electromagnetic properties, and can be artificially tailored for various applications. Based on metamaterials and metasurfaces, many abnormal physical phenomena have been realized, such as negative refraction, invisible cloaking, abnormal reflection and focusing, and many new functions and devices have been developed. The effective medium theory lays the foundation for design and application of metamaterials and metasurfaces, connecting metamaterials with real world applications. In this Element, the authors combine these essential ingredients, and aim to make this Element an access point to this field. To this end, they review classical theories for dielectric functions, effective medium theory, and effective parameter extraction of metamaterials, also introducing front edge technologies like metasurfaces with theories, methods, and potential applications. Energy densities are also included.

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