On the Near-field of an Antenna and the Development of New Devices

Funaro, Daniele

doi:10.48550/arxiv.1203.1229

Cited by 4 publications

(12 citation statements)

References 7 publications

(12 reference statements)

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“…In [4], the limit of the Maxwellian theory is attributed to the presence of nonhomogeneous terms. In my opinion, as rigorously analyzed in [8], even homogeneous Maxwell's equations in vacuum are not trouble free, displaying an extremely reduced space of solutions. The equations in this case are affected by an almost total lack of initial displacements satisfying both the conditions divE = 0 and divB = 0 (see my viewpoint in [9], chapter 1).…”

Section: Introductionmentioning

confidence: 83%

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Charging Capacitors According to Maxwell's Equations: Impossible

Funaro

2014

Preprint

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The charge of an ideal parallel capacitor leads to the resolution of the wave equation for the electric field with prescribed initial conditions and boundary constraints. Independently of the capacitor's shape and the applied voltage, none of the corresponding solutions is compatible with the full set of Maxwell's equations. The paradoxical situation persists even by weakening boundary conditions, resulting in the impossibility to describe a trivial phenomenon such as the capacitor's charging process, by means of the standard Maxwellian theory.

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Section: Introductionmentioning

confidence: 83%

“…where we recalled (8). Note that curlE = 0 on the boundaries Ω × {0} and Ω × {d} (lower and upper plates).…”

Section: Technical Preliminariesmentioning

confidence: 99%

Charging Capacitors According to Maxwell's Equations: Impossible

Funaro

2014

Preprint

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“…These issues are just sketched in this paper and are often underestimated in the design of a device. A transmitting antenna is an object transforming a certain signal by conferring to it the capability to travel in free space without further help from the source (see the final comments in the preliminary paper [32]). We believe that applied physics necessitates a better theoretical understanding of the mechanism of antenna emissions.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Highly Directive Biconic Antennas Embedded in a Dielectric

2020

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Designing antennas suitable for generating highly directive electromagnetic signals has become a fundamental task. This is particularly relevant for the development of efficient and sustainable point-to-point communication channels, and for energy transfer. Indeed, these are nowadays expanding areas of research. In order to deal with said particular wave phenomena, an extension of the electrodynamics equations is taken into account, where exact solitonic type solutions are admitted. These waves may have compact support and travel along a straight line, without dissipation, at the speed of light. The result suggests the design of biconic type antennas having specific properties that are numerically examined in this paper. The cones, supplied with an oscillating source, are embedded in a dielectric material of suitable shape, with the purpose of driving the signal in the proper direction. The computations based on the extended model are aimed toward simulating the possibility of generating peculiar wave behaviors, in view of practical implementations in the framework of point-to-point communications or wireless power transmission.

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“…[7], the solutions have been named free-waves. In this situation one has ( 6), ( 7), (8), plus the (geometric) relation:…”

Section: Extension Of the Maxwell's Modelmentioning

confidence: 99%

“…As we saw, this study requires an extension of the Maxwell's model in vacuum, since it seems natural to ask the divergence ρ to be different from zero (see also Ref. [8]). The spherical wave solution provided in ( 16) is already a step ahead in this investigation, because, for any given function f = 0, the divergence of the electric field does not vanish (with the exception of the singular case: f (θ) = 1/ sin(θ)).…”

Section: High-frequency Fields In Other Devicesmentioning

confidence: 99%

High Frequency Electrical Oscillations in Cavities

Funaro

2018

Mathematical Modelling and Analysis

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Abstract. If the interior of a conducting cavity (such as a capacitor or a coaxial cable) is supplied with a very high-frequency electric signal, the information between the walls propagates with an appreciable delay, due to the finiteness of the speed of light. The configuration is typical of cavities having size larger than the wavelength of the injected signal. Such a non rare situation, in practice, may cause a break down of the performances of the device. We show that the classical Coulomb's law and Maxwell's equations do not correctly predict this behavior. Therefore, we provide an extension of the modeling equations that allows for a more reliable determination of the electromagnetic field during the evolution process. The main issue is that, even in vacuum (no dielectric inside the device), the fast variation of the signal produces sinks and sources in the electric field, giving rise to zones where the divergence is not zero. These regions are well balanced, so that their average in the domain is zero. However, this behavior escapes the usual treatment with classical electromagnetism.

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On the Near-field of an Antenna and the Development of New Devices

Cited by 4 publications

References 7 publications

Charging Capacitors According to Maxwell's Equations: Impossible

Charging Capacitors According to Maxwell's Equations: Impossible

Highly Directive Biconic Antennas Embedded in a Dielectric

High Frequency Electrical Oscillations in Cavities

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