Journal ArticleDOI
The cylindrical antenna as a probe for studying the electrical properties of media
Ryan D. King,L. Scott +1 more
- Vol. 19, Iss: 3, pp 406-416
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TLDR
In this paper, the results of a new theory that is valid for electrically thin monopoles up to 5 λ λ/8 (dipoles with lengths up to 3.5 λλ/4) in length over all practical ranges of conductivity and permittivity of the ambient medium, including those characteristics of under- and overdense cold plasmas, are described together with their experimental verification.Abstract:
When a base-driven cylindrical monopole (or center-driven dipole) is immersed in an arbitrary medium, the electric and magnetic fields on its surface depend not only on its length and radius but also on the effective conductivity and permittivity of the medium. These fields can be explored and measured with small probes designed to travel along the cylindrical surface of the antenna. The interpretation of the observations depends on the availability of a general theory that correctly describes the distributions of current and charge on the conductor. The results of a new theory that is valid for electrically thin monopoles up to 5\lambda/8 (dipoles up to 5\lambda/4) in length over all practical ranges of conductivity and permittivity of the ambient medium, including those characteristics of under- and overdense cold plasmas, are described together with their experimental verification.read more
Citations
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Journal ArticleDOI
Electromagnetic waves and antennas above and below the surface of the earth
TL;DR: The well-known electromagnetic fields generated by infinitesimal dipoles in the presence of the earth are reviewed briefly with special reference to contributions by H. Bremmer as discussed by the authors.
Journal ArticleDOI
Insulated linear antenna: Theory and experiment. II
TL;DR: In this article, a recent analysis of the insulated antenna in a relatively dense ambient medium is summarized and its predictions are shown to be in good agreement with an extensive new set of measurements of the distributions of current and charge and the driving point admittances of air-insulated antennas in fresh and salt water.
Journal ArticleDOI
The insulated dipole antenna in a relatively dense medium
TL;DR: In this paper, the authors derived the properties of an insulated dipole antenna when the wavenumber of the surrounding infinite, homogeneous, and isotropic medium is large compared with that of the insulation.
Journal ArticleDOI
An Optically Coupled System for Quantitative Monitoring of MRI-Induced RF Currents Into Long Conductors
TL;DR: In this article, an optically coupled system with the potential to quantitatively measure the RF currents induced on long conductors such as guidewires is presented. But the system is not suitable for use with pacemaker leads.
Journal ArticleDOI
The many faces of the insulated antenna
TL;DR: In this article, the development of the insulated antenna is outlined from its beginnings as an ocean cable and the generalization of the theory from that applicable only to coaxial lines with an outer conductor of infinite extent to an insulated antenna embedded in a relatively dense medium that may be a dielectric or a conductor is described.
References
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Journal ArticleDOI
Theory of the Dipole Antenna and the Two‐Wire Transmission Line
TL;DR: In this paper, the properties of the dipole antenna are studied by an approximate procedure that makes use of the Wiener-Hopf integral equation, in particular, the input admittance and the radiation pattern are found.
Journal ArticleDOI
Measurement of ionospheric electron densities using an RF probe technique
J. E. Jackson,J. A. Kane +1 more
TL;DR: In this paper, the electron densities obtained by a propagation experiment and the rf probe technique were presented, and the electron density was obtained using a rocket flight July 4, 1957.
Journal ArticleDOI
Impedance of a short dipole in a compressible plasma.
TL;DR: Cylindrical dipole antenna field in compressible isotropic plasma, assuming triangular current distribution and deriving input impedance formula as mentioned in this paper, was used to evaluate the performance of the antenna.
Journal ArticleDOI
Currents, charges, and near fields of cylindrical antennas
R.W.P. King,T.T. Wu +1 more
Journal ArticleDOI
Computations of the Resistance of a Short Antenna in a Warm Plasma
TL;DR: In this paper, the input resistance of a shon filamental antenna in a warm isotropic plasma is computed for several antenna lengths and for a wide range of frequencies, which are compared with the result of the hydrodynamic equations.