Effects of the Plasma Frequency and the Collision Frequency on the Performance of a Smart Plasma Antenna

2015 ◽  
Author(s):  
Chen Zong-Sheng ◽  
Shi Jiaming ◽  
Cheng Li
Keyword(s):  
Collision Frequency ◽  
Plasma Frequency ◽  
Plasma Antenna

scholarly journals Potential Use of Cold Plasma Discharges for Frequency Reconfigurability in a Sievenpiper Mushroom Metasurface

2021 ◽  
Vol 11 (23) ◽  
pp. 11342
Author(s):  
Francisco Pizarro ◽  
Pablo Stuardo ◽  
Ricardo Olivares ◽  
Eva Rajo-Iglesias
Keyword(s):  
Parametric Study ◽  
Cold Plasma ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Stop Band ◽  
Plasma Discharges ◽  
Electronic Density ◽  
Full Wave ◽  
Insertion Losses ◽  
Potential Use

This article presents a parametric study using full-wave simulations about the potential use of cold plasma discharges to achieve frequency reconfiguration on a Sievenpiper mushroom metasurface. The study was done by inserting plasma tubes in between the patches of the mushroom structure, in three different positions with respect to the top of the metasurface, and varying the electronic density while keeping the plasma collision frequency. The obtained results show that it is possible to shift the stop-band generated by the metasurface around 25% towards lower frequencies for an electron density value inside the tubes of 1014 cm−3, when they are placed in between the top patches of the metasurface. Additional insertion losses are exhibited when operating near the plasma frequency.

Reflexion levels and coupling regions in a horizontally stratified ionosphere

1959 ◽  
Vol 252 (1004) ◽  
pp. 53-68 ◽  
Keyword(s):  
Collision Frequency ◽  
Plasma Frequency ◽  
Wave Theory ◽  
Electron Collision ◽  
Ray Theory ◽  
Radio Waves ◽  
Quartic Equation ◽  
Full Wave ◽  
Electron Collision Frequency ◽  
Full Solution

The propagation of radio waves through a horizontally stratified and slowly varying ionosphere is governed, in the case of oblique incidence, by a quartic equation (Booker 1938). Ray theory breaks down when two roots of this quartic are equal, for then coupling occurs between the characteristic waves, and full wave theory must be used. This paper is concerned with determining the conditions under which the two roots are equal; it is not concerned with the full wave theory. Values of the plasma frequency, and electron collision frequency, which lead to equal roots, are determined, and are exhibited in a set of curves. A full solution of the ‘Booker’ quartic is also given for a case of special interest. It is pointed out that the electric wave-field is unlikely to become very large in a slowly varying ionosphere, so that, if the ionosphere were irregular, scattering cannot be unduly enhanced by a plasma resonance.

A sensitive microwave interferometer for plasma diagnostics

1969 ◽  
Vol 3 (3) ◽  
pp. 371-375 ◽  
Author(s):  
J. R. Wallington ◽  
J. D. E. Beynon
Keyword(s):  
Phase Shift ◽  
Electron Density ◽  
Plasma Diagnostics ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Electron Collision ◽  
Microwave Attenuation ◽  
Electron Collision Frequency ◽  
Broad Dimension

More accurate methods of measuring microwave attenuation and phase are constantly being sought, particularly for such applications as plasma diagnostics. The microwave bridge technique described here was developed for the study of a quiescent plasma having an electron density of 1015 to 1018 m−3 corresponding to a plasma frequency of 3 × 108 to 1010 Hz, and an electron collision frequency of 1010 to 1011 s−1. The plasma had a broad dimension of 0·3 m. For such a plasma a probing frequency of 10 GHz was considered to be the most suitable; at this frequency the attenuation α and phase shift δβ expected were 0·1 < α< 50 dB and 1° < δβ < 1000° respectively.

scholarly journals Microwave Interferometry for Plasma Studies

1963 ◽  
Vol 16 (3) ◽  
pp. 439 ◽  
Author(s):  
LC Robinson ◽  
LE Sharp
Keyword(s):  
Electron Density ◽  
Microwave Radiation ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Plasma Temperature ◽  
Electron Plasma ◽  
Optical Path ◽  
Average Electron Density ◽  
Laboratory Plasmas ◽  
Average Electron

A beam of microwave radiation is a powerful and penetrating means of exploring the density and temperature of laboratory plasmas while causing minimal perturbation of the plasma. To a wave of frequency greater than the electron plasma frequency the plasma behaves like a dielectric, causing a change in the "optical" path which, when measured by interference techniques, yields the average electron density. The attenuation of the probing wave can give the collision frequency and hence the plasma temperature.

scholarly journals On Radiative Transfer Near the Plasma Frequency at Strong Coupling

1994 ◽  
Vol 147 ◽  
pp. 581-585
Author(s):  
Yu. K. Kurilenkov ◽  
H.M. Van Horn
Keyword(s):  
Refractive Index ◽  
Radiative Transfer ◽  
Absorption Coefficient ◽  
Strong Coupling ◽  
Dense Plasma ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Mean Free Path ◽  
Effective Collision Frequency ◽  
Effective Collision

AbstractThe effects of strong coupling on the frequency-averaged optical characteristics of plasmas, such as the Rosseland mean-free-path, are considered. The general expression for the Rosseland mean opacity has been analyzed in terms of the transverse dielectric function of a dense plasma and the frequency-dependent effective collision frequency. The corresponding values of the absorption coefficient and the refractive index for a dense plasma are presented at ω ≤ ωp up in obvious forms.

The Excitation of Resonances by a Dipole Antenna Inside a Hollow Cylindrical Plasma

1972 ◽  
Vol 50 (21) ◽  
pp. 2628-2637 ◽  
Author(s):  
G. L. Yip
Keyword(s):  
Electric Dipole ◽  
Radiation Resistance ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Dipole Antenna ◽  
Signal Frequency ◽  
Cylindrical Plasma ◽  
Point Electric Dipole ◽  
Practical Implications ◽  
Plasma Tube

The problem of the excitation of resonances by a dipole antenna inside a hollow cylindrical plasma is examined. The plasma is assumed to be cold, uniform, isotropic, and lossy. A transversely oriented point electric dipole antenna lying on the axis of the cylindrical plasma is the source under consideration. For a thin and lossless plasma, resonances are found to occur at the two frequencies corresponding to dipolar resonances in a hollow cylindrical plasma as derived earlier by, for example, Kaiser and Closs, and Vandenplas. In addition, there is also an antiresonance at the plasma frequency. The radiation resistance and radiation patterns of the plasma-covered dipole are presented to show the effects of the radii of the plasma tube, the signal frequency and the collision frequency. The possible practical implications of the present study as pertaining to the improvements of reentry communication and the excitation of plasma resonances in ionospheric irregularities are discussed.

Plasma frequency determination in YBa2Cu3O6+x as a function of oxygen content

1989 ◽  
Vol 50 (18) ◽  
pp. 2895-2901 ◽  
Author(s):  
N. Bontemps ◽  
D. Fournier ◽  
A.C. Boccara ◽  
P. Monod ◽  
H. Alloul ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Plasma Frequency ◽  
Frequency Determination
Sign in / Sign up

Export Citation Format

Share Document