A New Stripline-Based Atmospheric Pressure Microwave Plasma Sheet Source Designed for Surface Modification of Materials

A new type of microwave plasma source is presented in which plasma at atmospheric pressure is generated inside a quartz rectangular flat box placed in a stripline supplied by a 2.45 GHz coaxial line. The plasma has a sheet shape and is designed for surface modification. Electric field and power flux distributions, tuning characteristics, and power characteristics (ratios of radiated, absorbed, and entering power) are numerically studied for three configurations: open, semi-closed, and closed. The calculations show that near-zero radiation reduction is possible only for the closed configuration, while the ratio of radiated power to entering power is always greater than 30% for the other configurations. The moving plunger is not sufficient for the ratio of reflected to incident power to fall below 20% for both the closed and open configurations. This is possible for the semi-closed configuration, but then the radiated power is the highest. The experiment shows that for the same entering power, the plasma volume is largest for the closed configuration and smallest for the open configuration, which we attribute to the difference in radiated power. The plasma generated using the closed stripline configuration has a larger volume than plasma generated using the rectangular waveguide.

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Characterization of an Atmospheric-Pressure Argon Plasma Generated by 915 MHz Microwaves Using Optical Emission Spectroscopy

Journal of Spectroscopy ◽

10.1155/2017/6359107 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6

Author(s):

Robert Miotk ◽

Bartosz Hrycak ◽

Mariusz Jasiński ◽

Jerzy Mizeraczyk

Keyword(s):

Atmospheric Pressure ◽

Emission Spectroscopy ◽

Optical Emission Spectroscopy ◽

Microwave Plasma ◽

Argon Plasma ◽

Optical Emission ◽

Coaxial Line ◽

Plasma Source ◽

Stark Broadening ◽

Concentration Of Electrons

The paper presents the investigations of an atmospheric-pressure argon plasma generated at 915 MHz microwaves using the optical emission spectroscopy (OES). The 915 MHz microwave plasma was inducted and sustained in a waveguide-supplied coaxial-line-based nozzleless microwave plasma source. The aim of presented investigations was to estimate parameters of the generated plasma, that is, excitation temperature of electrons Texc, temperature of plasma gas Tg, and concentration of electrons ne. Assuming that excited levels of argon atoms are in local thermodynamic equilibrium, Boltzmann method allowed in determining the Texc temperature in the range of 8100–11000 K. The temperature of plasma gas Tg was estimated by comparing the simulated spectra of the OH radical to the measured one in LIFBASE program. The obtained Tg temperature ranged in 1200–2800 K. Using a method based on Stark broadening of the Hβ line, the concentration of electrons ne was determined in the range from 1.4 × 1015 to 1.7 × 1015 cm−3, depending on the power absorbed by the microwave plasma.

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A new type of non-thermal atmospheric pressure plasma source based on a waveguide bridge

Journal of Physics Conference Series ◽

10.1088/1742-6596/2064/1/012131 ◽

2021 ◽

Vol 2064 (1) ◽

pp. 012131

Author(s):

V N Tikhonov ◽

S A Gorbatov ◽

I A Ivanov ◽

A V Tikhonov

Keyword(s):

Atmospheric Pressure ◽

Microwave Plasma ◽

Short Circuit ◽

Atmospheric Pressure Plasma ◽

Plasma Source ◽

Gas Temperature ◽

Matched Load ◽

Microwave Source ◽

New Type ◽

Complexity Cost

Abstract A new type of microwave source of non-thermal atmospheric pressure plasmas, presented earlier by the authors, has both the characteristics of a dielectric barrier discharge (in terms of the configuration and low gas temperature) and an ability to form a “clean” plasma jet like a classical microwave plasma torch. However, the need to use a circulator leads to a significant increase in complexity, cost and weight of the installation as a whole. The basis of the presented plasma source is a three-decibel waveguide bridge with connection through a narrow wall. Both output arms of the bridge are loaded on identical short-circuited segments of waveguides. The discharge tube passes across the waveguides at a distance of a quarter of the wavelength from the short circuit. Since the output arms of the bridge are always loaded symmetrically, the generator’s power which is reflected from the short circuits or not be absorbed in the microwave discharge, enters the decoupled arm of the bridge that is connected to the matched load. Thus, the magnetron is protected from the reflected wave without the need for an expensive circulator, in any case.

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Surface Modification of Polycarbonate by an Atmospheric Pressure Argon Microwave Plasma Sheet

Materials ◽

10.3390/ma12152418 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2418 ◽

Cited By ~ 4

Author(s):

Dariusz Czylkowski ◽

Bartosz Hrycak ◽

Andrzej Sikora ◽

Magdalena Moczała-Dusanowska ◽

Mirosław Dors ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Modification ◽

Plasma Sheet ◽

Microwave Power ◽

Atmospheric Pressure ◽

Microwave Plasma ◽

Atmospheric Pressure Plasma ◽

Plasma Source ◽

Material Surface ◽

Pressure Plasma

The specific properties of an atmospheric pressure plasma make it an attractive tool for the surface treatment of various materials. With this in mind, this paper presents the results of experimental investigations of a polycarbonate (PC) material surface modification using this new type of argon microwave (2.45 GHz) plasma source. The uniqueness of the new plasma source lies in the shape of the generated plasma—in contrast to other microwave plasma sources, which usually provide a plasma in the form of a flame or column, the new ones provides a plasma in the shape of a regular plasma sheet. The influence of the absorbed microwave power and the number of scans on the changes of the wettability and morphological and mechanical properties of the plasma-treated PC samples was investigated. The mechanical properties and changes in roughness of the samples were measured by the use of atomic force microscopy (AFM). The wettability of the plasma-modified samples was tested by measuring the water contact angle. In order to confirm the plasma effect, each of the above-mentioned measurements was performed before and after plasma treatment. All experimental tests were performed with an argon of flow rate up to 20 L/min and the absorbed microwave power ranged from 300 to 850 W. The results prove the capability of the new atmospheric pressure plasma type in modifying the morphological and mechanical properties of PC surfaces for industrial applications.

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A Linear Microwave Plasma Source Using a Circular Waveguide Filled with a Relatively High-Permittivity Dielectric: Comparison with a Conventional Quasi-Coaxial Line Waveguide

Applied Sciences ◽

10.3390/app11125358 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5358

Author(s):

Ju-Hong Cha ◽

Sang-Woo Kim ◽

Ho-Jun Lee

Keyword(s):

Electron Density ◽

Microwave Plasma ◽

Circular Waveguide ◽

Coaxial Line ◽

Plasma Source ◽

Tangential Plane ◽

High Permittivity ◽

Deposition Area ◽

Extended Plasma ◽

Transverse Electromagnetic

For a conventional linear microwave plasma source (LMPS) with a quasi-coaxial line transverse electromagnetic (TEM) waveguide, a linearly extended plasma is sustained by the surface wave outside the tube. Due to the characteristics of the quasi-coaxial line MPS, it is easy to generate a uniform plasma with radially omnidirectional surfaces, but it is difficult to maximize the electron density in a curved selected region. For the purpose of concentrating the plasma density in the deposition area, a novel LMPS which is suitable for curved structure deposition has been developed and compared with the conventional LMPS. As the shape of a circular waveguide, it is filled with relatively high-permittivity dielectric instead of a quasi-coaxial line waveguide. Microwave power at 2.45 GHz is transferred to the plasma through the continuous cylindrical-slotted line antenna, and the radiated electric field in the radial direction is made almost parallel to the tangential plane of the window surface. This research includes the advanced 3D numerical analysis and compares the results with the experiment. It shows that the electron density in the deposition area is higher than that of the conventional quasi-coaxial line plasma MPS.

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Large Area Microwave Plasma Source Arrays for Ion-Assisted Sputtering of DLC and Surface Modification

10.14332/svc21.proc.0032 ◽

2021 ◽

Author(s):

Alexander Welsh ◽

Keyword(s):

Surface Modification ◽

Microwave Plasma ◽

Plasma Source ◽

Large Area

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A new type of non-thermal atmospheric pressure plasma source

Journal of Physics Conference Series ◽

10.1088/1742-6596/1393/1/012062 ◽

2019 ◽

Vol 1393 ◽

pp. 012062

Author(s):

V N Tikhonov ◽

I A Ivanov ◽

A V Tikhonov

Keyword(s):

Atmospheric Pressure ◽

Atmospheric Pressure Plasma ◽

Plasma Source ◽

Pressure Plasma ◽

New Type

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Basic characteristics for PEN film surface modification using atmospheric-pressure nonequilibrium microwave plasma jet

Electronics and Communications in Japan ◽

10.1002/ecj.10207 ◽

2010 ◽

Vol 93 (5) ◽

pp. 42-49 ◽

Cited By ~ 6

Author(s):

Toshifumi Yuji ◽

Takuya Urayama ◽

Shuitsu Fujii ◽

Yoshitoki Iijima ◽

Yoshifumi Suzaki ◽

...

Keyword(s):

Surface Modification ◽

Atmospheric Pressure ◽

Microwave Plasma ◽

Film Surface ◽

Plasma Jet ◽

Basic Characteristics

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Langmuir Probe Diagnostics with Optical Emission Spectrometry (OES) for Coaxial Line Microwave Plasma

Applied Sciences ◽

10.3390/app10228117 ◽

2020 ◽

Vol 10 (22) ◽

pp. 8117

Author(s):

Chi Chen ◽

Wenjie Fu ◽

Chaoyang Zhang ◽

Dun Lu ◽

Meng Han ◽

...

Keyword(s):

Electron Temperature ◽

Langmuir Probe ◽

Microwave Plasma ◽

Optical Emission ◽

Coaxial Line ◽

Plasma Source ◽

Optical Emission Spectrometry ◽

Emission Spectrometry ◽

Plasma Parameters ◽

Current Voltage

The Langmuir probe is a feasible method to measure plasma parameters. However, as the reaction progresses in the discharged plasma, the contamination would be attached to the probe surface and lead to a higher incorrect electron temperature. Then, the electron density cannot be obtained. This paper reports a simple approach to combining the Langmuir probe and the optical emission spectrometry (OES), which can be used to obtain the electron temperature to solve this problem. Even the Langmuir probe is contaminative, the probe current–voltage (I–V) curve with the OES spectra also gives the approximate electron temperature and density. A homemade coaxial line microwave plasma source driven by a 2.45 GHz magnetron was adopted to verify this mothed, and the electron temperature and density in different pressure (40–80 Pa) and microwave power (400–800 W) were measured to verify that it is feasible.

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