Plasma Antenna Research Articles

Radiation Characteristics of Guided and Leaky modes for a Plasma Column Antenna

A substantial problem for the radiation of a plasma column antenna is investigated. By means of the study on electromagnetic (EM) waves propagating along the plasma column and acting with plasma, it is found that a plasma column can radiate the EM energy when it works as two kinds of operation modes. The first one is a guided mode which leads to a surface current radiation, and its operation condition is obtained by determining the relation of plasma frequency and signal frequency. The second one is a leaky mode which causes a leaky wave radiation, and its operation condition is presented by analyzing normalized complex propagation constant. With further dealing with the leaky mode, its far field is got by applying the Schelkunoff’s equivalence principle on the surface of the plasma column. Radiation patterns of two kinds of modes are presented in their respective operation frequency bands, and reveal the radiation properties of the plasma antenna. The presented results are very helpful for further investigation in the design and application of plasma column antenna DOI : http://dx.doi.org/10.11591/telkomnika.v12i1.3500

Research on radiation characteristic of plasma antenna through FDTD method.

The radiation characteristic of plasma antenna is investigated by using the finite-difference time-domain (FDTD) approach in this paper. Through using FDTD method, we study the propagation of electromagnetic wave in free space in stretched coordinate. And the iterative equations of Maxwell equation are derived. In order to validate the correctness of this method, we simulate the process of electromagnetic wave propagating in free space. Results show that electromagnetic wave spreads out around the signal source and can be absorbed by the perfectly matched layer (PML). Otherwise, we study the propagation of electromagnetic wave in plasma by using the Boltzmann-Maxwell theory. In order to verify this theory, the whole process of electromagnetic wave propagating in plasma under one-dimension case is simulated. Results show that Boltzmann-Maxwell theory can be used to explain the phenomenon of electromagnetic wave propagating in plasma. Finally, the two-dimensional simulation model of plasma antenna is established under the cylindrical coordinate. And the near-field and far-field radiation pattern of plasma antenna are obtained. The experiments show that the variation of electron density can introduce the change of radiation characteristic.

A Two Element Plasma Antenna Array

This theoretical study presents the characteristics of plasma monopole antennas in the VHF/UHF range using finite difference time domain (FDTD) simulation. Results show that more broadband characteristics can be obtained by increasing the diameter of the plasma tube and that the minor lobes diminish in intensity as diameter increases. Furthermore, the nulls are replaced by low level radiation. Since the collision frequency, which is a function of gas pressure, represents the loss mechanism of plasma, decreasing its value increases the gain and radar cross section (RCS) of the antenna. Theoretical modeling shows that at higher plasma frequencies with respect to the signal frequency, the gain and radar cross section of the plasma antenna are high enough and that the impedance curves are altered as the plasma frequency varies. Using these preliminary studies, mutual impedance and gain of a broadside array of two parallel side-by-side plasma elements is presented.

Resonant RF network antennas for large-area and large-volume inductively coupled plasma sources

Large-area and large-volume radio frequency (RF) plasmas are produced by different arrangements of an elementary electrical mesh consisting of two conductors interconnected by a capacitor at each end. The obtained cylindrical and planar RF networks are resonant and generate very high RF currents. The input impedance of such RF networks shows the behaviour of an RLC parallel resonance equivalent circuit. The real impedance at the resonance frequency is of great advantage for power matching compared with conventional inductive devices. Changes in the RLC equivalent circuit during the observed E–H transition will allow future interpretation of the plasma–antenna coupling. Furthermore, high power transfer efficiencies are found during inductively coupled plasma (ICP) operation. For the planar RF antenna network it is shown that the E–H transition occurs simultaneously over the entire antenna. The underlying physics of these discharges induced by the resonant RF network antenna is found to be identical to that of the conventional ICP devices described in the literature. The resonant RF network antenna is a new versatile plasma source, which can be adapted to applications in industry and research.

Design of Surface-Wave Sustained Plasma Flat Panel Lamps

Surface-Wave sustained plasma (SWP) source is a novel plasma source technology. It can generate large scale plasma at low pressure. SWP is fit for the plasma antennas because of exciting from one pole. The flat panel lamps are widely used in many fields. In this paper, a flat panel lamp is designed based on the Surface-Wave sustained plasma (SWP) source. The design blueprints are introduced and discussed. The design programs of single luminous surface and double luminous surfaces SWP flat panel lamps are introduced. The experimental apparatus is designed for the SWP flat panel lamps in the end.

Study on System for Establishing and Sustaining Plasma Used to Antenna

To study the model of plasma antenna, a system intended to establish and sustain plasma with RF power was described in this paper. This system was made as a modular design, a feature that facilitates changing of operating frequency, RF power. A univariate optimization algorithm was used to achieve impedance matching (coefficient< 5%) in the system, therefore some key experimental data were measured accurately. Experiments showed that there is a difference between establishing power and sustaining power of plasma, and indicated the function of the length of the plasma column vs. square root of RF power.

Reception of longitudinal vector potential radiation with a plasma antenna

To help resolve the long-running debate between physicists and engineers regarding the existence of the magnetic vector potential, herewith we describe an experiment demonstrating reception of time-harmonic vector potential radiation at 1.3 GHz.

Physics and technology in the ion-cyclotron range of frequency on Tore Supra and TITAN test facility: implication for ITER

To support the design of an ITER ion-cyclotron range of frequency heating (ICRH) system and to mitigate risks of operation in ITER, CEA has initiated an ambitious Research & Development program accompanied by experiments on Tore Supra or test-bed facility together with a significant modelling effort. The paper summarizes the recent results in the following areas: Comprehensive characterization (experiments and modelling) of a new Faraday screen concept tested on the Tore Supra antenna. A new model is developed for calculating the ICRH sheath rectification at the antenna vicinity. The model is applied to calculate the local heat flux on Tore Supra and ITER ICRH antennas. Full-wave modelling of ITER ICRH heating and current drive scenarios with the EVE code. With 20 MW of power, a current of ±400 kA could be driven on axis in the DT scenario. Comparison between DT and DT(3He) scenario is given for heating and current drive efficiencies. First operation of CW test-bed facility, TITAN, designed for ITER ICRH components testing and could host up to a quarter of an ITER antenna. R&D of high permittivity materials to improve load of test facilities to better simulate ITER plasma antenna loading conditions.

An analytical approach to light scattering from small cubic and rectangular cuboidal nanoantennas

At optical frequencies metals behave as an electron plasma and conventional antenna designs need modifications when transferred to this regime. In contrast to antenna theory and to the effective wavelength picture, the position and width of the dipolar resonance of a rectangular cuboidal plasmonic nanoantenna scales nonlinearly with its length, width and height, as shown in this paper directly by analytical formulae. Moreover we show that the quality factor calculated for different sizes varies significantly with size, in contrast to the quasi-static approximation which predicts invariance. We present analytical expressions that provide a tool for direct and precise calculation of the dipolar plasmon resonance which can be applied to the antenna design process. These expressions enable both physical insight and the quick exploration of a wide range of parameters to tailor the plasmon resonance response or scattering by nanoparticles, for either metals or dielectrics, for numerous promising applications in optical sensor, photovoltaic and light emitting device design.

Characterization of the Fabrication Process of Rolled LTCC Structures

This work focuses on the fabrication and assembly of cylindrical plasma containment tubes using DuPont's 951 low temperature co‐fired ceramics (LTCC) for use in miniature electrostatic thrusters. The tube is used to contain argon plasma, which is generated by a spiral inductively coupled plasma antenna, which is also fabricated in LTCC. The tube also interfaces with two electrically biased grids on the opposite end, which accelerate the plasma out of the tube. These interfaces are highly dependent on the dimensions and tolerances of the containment tube. The development of the fabrication process will be presented for the incorporation of the tubes and grids onto the base as a single structure. This includes constructing the antenna base, shaping the “rolled” LTCC containment tube using a jig and isostatic press, and integrating the tube and antenna base during the firing. Following the fabrication, measurements will be taken to determine tube circularity and hermeticity of the seal at the interface between the tube and the antenna base. The results will be presented and characterized to evaluate the effectiveness of the structure as well as the documentation of the development of a rolled LTCC tube structure integrated with a planar LTCC antenna base.

Radiation characteristics and electromagnetic compatibility of 5-20 KHz ac plasma antenna

In order to meet the needs of engineering, plasma antenna must meet the requirement in terms of gain, bandwidth, noise, electromagnetic compatibility (EMC) and so on. A plasma antenna prototype was established by 5-20 KHz high voltage ac power, whose radiation characteristics and electromagnetic compatibility was tested and analyzed. Results show that 5-20 KHz ac plasma antenna is of broadband impedance characteristics. Compared with 50 Hz ac plasma antenna, the noise reduces and the gain increases from 150 MHz to 350 MHz. When plasma antenna connected to radio is on, the radio can receive signals. The interference to radio is much lower than RF surface wave plasma antenna and 50 Hz ac plasma antenna. It is of a certain electromagnetic compatibility.

Direct, spectroscopic measurement of electric fields in a plasma-RF antenna interaction region in Tore Supra

Balmer-series spectral line profiles of deuterium emission near a lower-hybrid (3.7 GHz) wave, high power (1–4 MW) launcher were measured with high-spectral resolution in the Tore Supra tokamak and fitted to an atomic physics model which includes both Zeeman and dynamic Stark effects. The magnetic field is static and the electric field is assumed to be monochromatic at 3.7 GHz. The determined strength and direction of the high-frequency electric field is found to be in good agreement with the results of a simulation that computes the propagation of these lower hybrid waves into the plasma in the region around the launch antenna and specifically in the region of estimated peak emission contributing to the measurement. This agreement indicates feasibility for the use of dynamic Stark effect spectroscopy to study interaction at the plasma antenna interactions in a fusion plasma environment.

Computer Simulation of a Plasma Vibrator Antenna

The use of new plasma technologies in antenna technology is widely discussed nowadays. The plasma antenna must receive and transmit signals in the frequency range of a transceiver. Many experiments have been carried out with plasma antennas to transmit and receive signals. Due to lack of experimental data and because experiments are difficult to carry out, there is a need for computer (numerical) modeling to calculate the parameters and characteristics of antennas, and to verify the parameters for future studies. Our study has modeled plasma vibrator (dipole) antennas (PDA) and metal vibrator (dipole) antennas (MDA), and has calculated the characteristics of PDAs and MDAs in the full KARAT electro-code. The correctness of the modeling has been tested by calculating a metal antenna using the MMANA program.

PROSPECTS FOR THE DEVELOPMENT OF PHASED ANTENNA ARRAYS

This article describes the main achievements in the development of phased antenna arrays (par) in the past decade. Provides an overview of the most famous systems based on the PAR and PAR based on MMIC technology - PAR in radar stations, PAR to control the laser and optical beams. The existing options for the design of the PAR:ferroelectric antenna array; plasma antenna with electronic scanning; reflective grating on 100-mm semiconductor wafers; wideband antenna arrays with aperture; antenna arrays with digital beam forming.

A DISPERSIVE CONFORMAL FDTD TECHNIQUE FOR ACCURATE MODELING ELECTROMAGNETIC SCATTERING OF THZ WAVES BY INHOMOGENEOUS PLASMA CYLINDER ARRAY

A dispersive conformal FDTD method has been proposed to accurately model the interface between two adjacent dispersive mediums and implemented to study the scattering of THz electromag- netic (EM) waves by inhomogeneous collisional plasma cylinder array. The method is based on the technology of area average, which is dif- ferent from existing dispersive conformal FDTD schemes. Numerical results show that the proposed method enhances the accuracy level compared to the staircasing FDTD scheme involved in the inhomoge- neous plasma. It is interesting to flnd that the THz EM waves can propagate through the plasma array more easily with higher frequen- cies or larger separations, hence the scattering width in the backward direction becomes smaller, and the forward scattering exhibits a little difierent. This study will be useful for further designing intelligent plasma antenna arrays in the THz band and terahertz reentry teleme- try through plasma.

Radiofrequency plasma antenna generated by femtosecond laser filaments in air

We demonstrate tunable radiofrequency emission from a meter-long linear plasma column produced in air at atmospheric pressure. A short-lived plasma column is initially produced by femtosecond filamentation and subsequently converted into a long-lived discharge column by application of an external high voltage field. Radiofrequency excitation is fed to the plasma by induction and detected remotely as electromagnetic radiation by a classical antenna.

Electro-physical property of plasma jet generated by burning chemicals as antenna

AbstractThe application of pulsed power to transient radiofrequency/microwave radiation for warhead/projectile payloads is currently a significant area of research. In this paper, the far-field radiative property of a plasma antenna is analyzed. Then, a plasma jet is generated by burning chemicals, in which the electron concentration and collision frequency are diagnosed, and the electric conductance is calculated. Finally, the feasibility to apply the plasma jet as antenna is investigated by analyzing the radiative pattern. The dependency of pattern on plasma electron density, collision frequency, and plasma wake radius is calculated and analyzed.

Essential Characteristics of Plasma Antennas Filled with He-Ar Penning Gases

Based on the essential theory of Penning gases, the discharge characteristics of He-Ar Penning gases in insulating tubes were analyzed qualitatively. The relation between the effective length of an antenna column filled with He-Ar Penning gases and the applied radio frequency (RF) power was investigated both theoretically and experimentally. The distribution of the plasma density along the antenna column in different conditions was studied. The receiving characteristics of local frequency modulated (FM) electromagnetic waves by the plasma antenna filled with He-Ar Penning gases were compared with those by an aluminum antenna with the same dimensions. Results show that it is feasible to take plasma antennas filled with He-Ar Penning gases as receiving antennas.

Characterization of the Fabrication Process of Rolled LTCC Structures

This work focuses on the fabrication and assembly of cylindrical plasma containment tubes using DuPont's 951 Low Temperature Co-fired Ceramics (LTCC) for use in miniature electrostatic thrusters. The use of LTCC allows for robustness post-firing yet flexibility in the “green” un-fired state. Some of the main advantages of this flexibility include the ability to stack or roll the LTCC sheets into various shapes as well as incorporating embedded electrical interconnections using silver paste on the rolled layers. The tube is used to contain argon plasma, which is generated by a spiral Inductively Coupled Plasma antenna and is also fabricated in LTCC. The tube also interfaces with two electrically biased grids on the opposite end, which accelerate the plasma out of the tube. These interfaces are highly dependent on the dimensions and tolerances of the containment tube. The development of the fabrication process will be presented for the incorporation of the tubes onto the base as a single structure. This includes constructing the antenna base, shaping the “rolled” LTCC containment tube using a jig and isostatic press, and integrating the tube and antenna base during the firing. Following the fabrication, measurements will be taken to determine the tube circularity and the hermeticity of the seal at the interface between the tube and the antenna base. The results will be presented and characterized to evaluate the effectiveness of the structure as well as the documentation of the development of a rolled LTCC tube structure integrated with a planar LTCC antenna base.

Numerical Modelling of Cylindrical Monopole Plasma Antenna Excited By Surface Wave

In the recent research on cylindrical monopole plasma antenna excited by surface wave, many meaningful results about plasmas antenna, e.g. the analysis of physical characteristics, numerical calculation methods, software simulation, diagnosis of parameters have been obtained. But the precise model of monopole plasma antenna according to its three-dimensional structure has not been proposed yet. There are few papers concerning this topic in previous academic journals. This paper analyzes three-dimensional distributions of electric and magnetic fields around monopole plasma antenna. The related formulas and equations of the model are derived by applying molecular dynamic theories and Maxwell-Boltzmann equations. In addition, numerical simulation methods are employed to verify the validity of proposed model.